Thoughts on installing a 'cooler' thermostat...???

I see that German 160-something thermostats are available for these cars - anybody put one in for the street - thoughts???

Thoughts? I think when the stock system is properly maintained and functioning correctly that its more than adequate. Lower temp t-stats do not increase the capacity of the system; the 3rd radiator does though [Wait - as a tip you might already have the 3rd radiator, right?]. If you are looking for something to tinker with, clean the radiators.

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Yes, Tip has the center radiator. Radiators are clean.

I have completed the evaluations on the LN Engineering 160F thermostat and the average temperatures I have seen logged this summer were 12F between the stock vs 160 thermostat. I like the unit because it reduces the thermal shock that the engine sees when the thermostat does begin to open. I recently completed an engine that made 87HP more than it did stock (added 400ccs of displacement through a big bore, added CR and headwork) that engine with the low temp Tstat ran cooler than the stock engine that it replaced with no other changes to the cooling system or car. The difference was almost 20 degrees. Next month I have a track day and we'll be swapping thermostats between both my Boxster and 911 test vehicles on saturday evening so we can data log the differences on the same track and the same ambient temps, speeds and drivers... It does work, EVERY engine I create gets one standard..

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Jake - I'm merely looking to reduce normal operating temp. Is it DIY-able to change the t-stat??? My depth of P-car repairs is stuff like changing to pressure fed tensioners on older 911's (have done 3 of them - easy), complete brakes and other 'easy' stuff - plugs on 993's (hard).

Unless the lower thermostat also increase the flow of the coolant, it will not change the coolant tenmperature by anything measurable. Even running without a thermostat will only lower the coolant temperature by a few degrees, and definately no where close to 12F lower than the normal 194F. This is for both the 3.4 and 3.6 engines.

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Strange - when I install a cooler t-stat in my Impala SS, the car runs so cold that it will not heat the passenger compartment in the winter time. It runs better in the summer though - nice and cool - you can run just a tad bit more advance thru the computer that way - safely. The whole idea behind the LT1 engine was to route the coolant thru the heads in a reverse routing and drive the head temp down enough to crank up some serious advance on pump gas. The LT1 Chebby Impala is a beast because of it. If the 996 cooling capacity is up to it, a cooler t-stat should result in measurably cooler running temps no problem.

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I didn't know we were talking about Chevy Impallas. I have studied the cooling systems of the Porsche 3.4 and 3.6 engines extensively over the past 5 years and it is impossible to run the engine with a coolant temperature at 182F in any climate. Whether it is 0F outside or 100F, short of coasting into a cool breeze, you will never see 182F once the engine has warmed up, even driving moderately. The biggest drop in temperatures occured in below freezing temperatures without a thermostat where we recorded a 4% drop from targeted coolant temperature . Cooling system was stock with no modifications. Increasing air flow over the radiators had a similar effect while running the stock thermostat. Without an increase in fluid and/or air flow, you will see no reduction in coolant temperatures.

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Jake Raby has indicated the opposite of what you say. I'd be inclined to go with the experts in this case.

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So, you actually think Jack claimed he can reduce your coolant temperatures to 182F? He made no such claim. Like I said, it is a fact of physics that unless the flow of the fluid is changed, there will be no change in coolant temperature. Everything being equal, a opening setting on a thermostst can only be used to increase the coolant temperature. It would take a change in the design of the thermostat to either increase or decrease the volume of coolant flow to have any cooling effect. Otherwise, simply having the thermostat open earlier will just take longer for the engine to reach the same engine it would reach with the stock thermostat.

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Here's the answer to your question above. If running thinner cylinder walls from boring and higher compression ratios on a stock cooling system with just a lower t-stat reduces overall coolant temps, then the stock engine should easily benefit from one.

1999porsche911, Let�s advance a hypothesis: A 911 Porsche cooling system is designed to have a greater capacity to shed heat then the engine�s ability to create heat. So a controlling device is needed to control these two at a predetermined point to facilitate efficient operation of the engine, say 190 degrees. Do you find this a reasonable assumption? I think the physics of this might be: If one runs a water cooled engine at maximum heat load with the cooling system operating at maximum heat dissipation and both systems, generation and dissipation, reach equilibrium at 220 degrees with a fully open thermostat. The temp the thermostat fully opened, 160 or 180 or 110 would have had no effect at end point. I postulate that: If one were to run the same engine at 50% heat load with the same capacity cooling system with no thermostat the temperature at equilibrium would be lower, for arguments sake 130 degrees. If so adding a 160 or 180 thermostat at the output of the heat producer (engine) would be the controlling factor of when the engine reached equilibrium - 160 or 180 degrees. The cooling system with its extra capacity would be much cooler then the engine.

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I think installing a cooler thermostat will result in a cooler running engine if the radiator system is up to it. Simple. I will report the results later.

So the net net is that by opening the thermostat earlier with a lower temp thermo it takes you a lot longer to reach the equilibrium temp between the oil and the water heat exchanger. You will still get there but it just takes longer and in some cases due to the brief drive or conditions you may never reach it. Now adding the 3rd radiator (for coolant) adds additional coolant capacity and "cooling surface" which is another story altogether.

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The 'net net' is that by running a cooler thermostat together with a capable cooling system, your car will run cooler. Like I said before with the Impala real life example - with a cooler, sooner opening t-stat, it never ever really reached a condition in the winter time where enough hot water was generated to heat the cabin to a comfortable temp. The 'net net' for the Impala was that the Summer running temps were lowered significantly and with a computer reflash the car picked up tangible power. In the case of the 996, I am looking simply to lower the constant operating temp and lower hot soak starting point. The sticking point for the 996 is if it's cooling system is already operating at max capacity or near max capacity at 180 - 190 degree already, which given the engineering issues associated with the 996 engine, it would not surprise me. (my gut feeling is that the engine life issues center on cooling problems + other stuff) So if there is very little extra cooling capacity with the three radiators and those long coolant runs, the 160 deg stat might be a wash. But I intend to find out if the t-stat is diy-replaceable. BTW: Tips already have the center cooler.

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That is not true. Right now, your 996 thermostat is fully open at 182F. Your coolant temperature is around 194F at best. If you simply make the thermostat open at 160F or even 50F, how would this cool down your engine? Your real world example with your impalla either had an orginal thermostat that was opening at a temperature that exceeded the cooling capacity of the system or in addition to opening at a cooler temperature, it also changed the flow.

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Nope - it didn't change the flow. Just opened sooner and ran cooler. Why do cars run cooler if you simply remove the t-stat then?

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Some cars run cooler without the thermostat and some run hotter. The reason there is a change is because you have removed the restriction of the thermostat from the flow path. There is an optimum speed at which the coolant should flow. Too slow and it absorbs too much heat. Too fast and the radiators have less time to cool it.

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+1 Amazing how few people know and/or understand this.

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The factory 996 t-stat begins to open at 187 degrees and is fully open at 210 degrees. With the car in motion and cooling air flowing across the heat exchangers, the car will run 15 - 20 degrees cooler - good stuff or track use or at highway speeds - kind of a wash for stop & go driving. The best case would be to run the cool t-stat and have the ability to activate the two aux cooling fans earlier than the Porsche design. I think the Porsche fans come on at about 210 degrees or so - somebody out there has those figures memorized. So if you could either manually turn them on or have the ECU turn them on at say, 185 degrees or so, you'd have a cooler running engine. 210 degrees in darn hot - On my 993's I was able to get the engine oil heat exchanger cooling fans to come on early or whenever I wanted and it was a real boon to stop & go temp management.

so why not do this on ALL cars? (not just P-Cars) I agree that having the temp lower is more comforting while you are just looking at tailights in stop and go traffic....and higher = scary feelings..... but dont all cars experience the same thing

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Your numbers are all wrong for the 996 thermostat. Pull it out and test it and you will see. Many of us already turn our fans on earlier and maintain much cooler temps than stock, even with the stock thermostat.

My 996 runs exactly on the dot at 193 degrees in any weather, but will hit 212 when stuck in traffic in 90 degree weather, but goes back to 193 when the car is moving again. I found that by having A/C on reduced the coolant temp by couple of degrees.

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The reason your engine cools down at certain engine temps when you turn the AC on is that when the engine temp is below 196F, and AC off, there is no fan operation. Turning the AC on when you're below 196F kicks on the low speed fans, offsetting the additional load and heat placed on the engine from running the compressor. Turning the AC on when engine temps are above 196 will increase coolant temperatures, everything else being equal.

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What we need is the specs for how the t-stats open. What do you think the numbers are for the t-stat: beginning to open and fully open? Where did you get the numbers?

A lower opening thermostat will do nothing but effect emmisions, require a longer time for your heater to produce hear, take longer for the oil and coolant to reach proper temperature. What it will no do is lower your coolant temperatures.. Coolant temperature is a function of input heat, radiator performance, coolant flow, airflow and the type of fluid used in the system. Your thermostat is a device designed to warm up the engine and NOT to cool it down. Marketing can be very powerful, but don't get sucked into believing the impossible just because alot of others do. It's all about making money, and nothing else.

Ok, I heard this before about once your t-stat is open, that is all the system can do. I dont think so. Think about it, if you can meet operating temp in cold air, then your car would overheat in hot air because there is no more capacity for cooling in the hotter ambient temps. This is not the case. Your t-stat is constantly fluctuating to maintain coolant temp it is rated at, not stay fully open.

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+1 and your other comments. Thanks for trying to enlighten others although you must feel like

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It doesn't work that way. Your logic is all wrong. Think efficiency.

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Every car/truck will reach, lets say, 180 degrees in 0 degree weather just as it will in 120 degree weather. So, to say once your t-stat is open (180 degrees) the cooling system is running at 100% duty is simply not true. If that was the case, your car would overheat in the 100 degree weather since it was at 100% duty in the 0 degree temps. T-stats do fluctuate flow for regulating coolant temps.

From http://www.aa1car.com/library/overheat.htm "If the thermostat needs to be replaced, install one with the same temperature rating as the original. Most cars and light trucks since 1971 require thermostats with 192 or 195 degree ratings. Using a cooler thermostat (160 or 180) in an attempt to "cure" a tendency to overheat can increase fuel and oil consumption, ring wear and emissions. On newer vehicles with computerized engine controls, the wrong thermostat can prevent the computer system from going into closed loop resulting in major performance and emission problems if the engine fails to reach its normal operating temperature." The easily observed fact that the coolant temp DOES rise on a hotter day with lower air flow, proves that, at that point the T-stat is full open. This does not happenin the middle of winter, yett he coolant temp is still the same for normal, in motion, operation. Physics dictates that the T-stat can not be full open under those circumstances. You can increase the cooling capacity of a radiator (remove heat from the coolant) in pretty much only a few ways. 1. Increase air flow. 2. Cooler inlet air flow 3. Coolant that has a better heat transfer characteristic. 4. Slow down the coolant flow through the radiator. The problem with #4 is that it is a closed loop sytem, so while the delta T will be lower at the radiator outlet, as 1999 states, the coolant may also pick up too much engine heat, thereby raising the inlet temp, or worse, boiling the coolant in the coolant passages and cause hydrolock. In general, higher flow through the system regualtes temperature better (reduce time of coolant control loop). I predict that in the near future we will see most cars go to electric coolant pumps that vary speed to load & heat inlet/outlet. I'm really surprised it hasn't happened already.

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Sounds like hodgepodge references from printed material that has been partially memorized for a test - not totally unfactual or wholly inaccurate, but a lot of uneccessary fill. Bottom line is that a 160 degree t-stat will keep a 996 running cooler while underway. BTW: what is your reference to the objection to my 996 t-stat numbers before. I want to look them over pls.

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I thought the water pump is used to regulate flow. The purpose of the thermostat is to let the engine get to operating temperature as quickly as possible.

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That assumes that the engine temperature is at or slightly above the t-stat specs and that the cooling system has the ability to offset any additional heat gain. In the case of Porsche's t-stat, it is not, except under specific conditions. If your engine is running at 200F which is far in excess of the opening of the t-stat, there is no variable control of the coolant flow by the stat.. Even at 70 mph without a thermostat and ambient temps of 10F, I have never seen my coolant drop below 185F. Just install a lower t-stat and you'll see you still will get temps above 210F. Your temps can get that high even without a thermostat.

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Probably because the 996 standard cooling system with the 2 little heat exchangers are on the hairy edge of efficiency. Typical Porshce engineering to shave toleranaces so close - has it's good points and bad points.

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The thermostat effects flow because of the space it takes up. In the old days when thermostats were removed, you often had to install a specific size washer on the inlet to reduce the amount of flow.

Putting a lower thermostat does nothing...unless your goal is to run the car cooler than the open point of the thermostat (184 deg or whatever it is). So above 184 deg -> it's all about the driving speed, the number of radiators, coolant ratio, and lastly when the fans turn on. If you want to modify anything here, I'd hack the fans so turn on earlier (aka manual switch or temperature sensor). Below 184 degrees -> It's all about driving speed, engine RPM, ambient temperature etc...since no coolant is flowing. The only remote possibility is the 184 deg stock thermostat is the flow restrictor in the coolant system and the 160 deg thermostat flows better removing this restriction....however at this point a "better flowing" 184 deg thermostat would do the same thing. Hope this makes sense.

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Raby claims 20 degrees less with higer compression and thinner cylinder walls using lower temp t-stats.

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20 degrees less than what and under what conditions. I guarantee you that a mod consisting of only a themostat temperature change will not reduce temps by 20F from the target of 194F or even from 200F even if the ALMIGHTY himself made that claim. It's comparatively easy to reduce temps from 220 down to 200.

I know it is very hard to believe but the t-stat opens and closes depending on coolant temp. If it cools enough, the t-stat can actually restrict coolant flow to maintain operating temps. If my car, and like Robin said, maintained the same temps in both ends of the temperature spectrum (cold vs hot), proves it just doesnt open all the way and the engine coolant temps are solely at the mercy of the cooling systems total cooling ability. If all the t-stat would do is open all the way, how in the world could your car maintain the same temperature in different temps? It wouldnt. Forget stop and go. Mine would get hot too in both temp ranges if there wasnt sufficient airflow. The t-stat opens and closes to regulate temp. That is its job. Warm up is just the beginning.

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If your engne temperature is 193F your thermostat is not opening and closing. That is a fact. It dioes not operated on the bubble. Pull it out of your car and test it. We're not talking theory here, but real world operation. Better yet, remove it and drive your car then come back and report to us that you see the same high and cool coolant temps, then explain to us how that is possible. Your thermostat is fully open and changes in temps results from many other conditions such as engine load, car speed, engine speed, ambient temps, sun or clouds; any of which will dramtically effect temperature. If the only variable that is changed is the point at which the thermostat opens, this is not and cannot be any change in coolant temperatures, just a change in the time it take to reach the same temperature. The stock stat on the 996 will not close again once it is open except under very specific conditions. The engine is just too hot to begin with and the cooling system is too inefficient.

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+1

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Once again, how does operating temp maintain in 0 degrees outside temps or 100 degrees outside temps? The t-stat opening and closing. I did the washer thing on my '69 Camaro. I 100% agree. You dont know what temp you will get unless you run it. Peace out, Ive got better things to do.

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The same way the engine maintains its temperature WITHOUT a thermostat. It's not that complicated.

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A water cooled engine operating w/o a t-stat will seek temperature equilibrium based on engine heat generation (combustion, exhaust flow, etc) against it's ability to shed the same thru the radiator efficiency, flow and characteristics of the coolant and/or antifreeze qualities, wind thru the engine bay, other quantifiable intangibles (auto transmission cooled by engine radiator, etc.), etc. If the cooling system is up to it and there is good fresh air exchange happening in the engine bay, it will run very cool, maybe too cold even. Would be interesting to see what the 996 cooling system is 'up to'. My guess is that without the ability to enrgizethe cooling fans on before 210 degress, it might run 10-15 degrees cooler while the car is in motion. All in all, the 996 cooling systems sucks bad -- blows bad -- or ever how you want to characterize it. In my estimation these engines slowly cook themselves to death after they are shutdown. Too bad the aux cooling fans come on so 'late' - I think it would help if they came on about 20 - 25 degrees earlier - might help lower the initial hot soak cycle. Also need a post-shutdown electric circulator to flow the coolant thru the system to reduce hot soak badness. tsk -tsk... I still intend to try a cooler t-stat and will report my observations.

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A washer in the t-stat housing will not make an engine maintain, say 180 degrees like a thermostat will. It will fluctuate. I agree that is a cooling is at 100% duty, a lower thermostat may not help lower temps. But, at any temps within the efficiency range, the car will run cooler. I seen it time and time again. Fox body Mustangs will not run properly with a 160 degree thermostat, they never get out of warming up. So, they do work. Will they be as effective on the 996? Raby claims yes.

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Do you read my posts before responding? NOTHING of what you are responding to was said by me. It seems that you can't debate the issue being discussed and keep throwing in unrelated topics to cover yourself. Just do the mod yourself and pretend that you are running cooler.

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Where did I throw in unrelated topics?

We are already working in this direction for the M96... The packaging of the system is a pain, thats the problem.. Data that can't be argued with is on the way... I just need a few more near 100 degree days and this summer has been wayyyy too cool for us here... BTW- The low temp T stat was tested at -28F this year in Chicago with zero adverse effects on cabin heat. I guess if the factory didn't do it, then it doesn;w work... Right guys??? If its factory I tend not to run it on purpose! It wouldn't be hotrodding if we played by the rules.

You guys should debate much less volatile topics, like....... which weight of oil to use in the 996.

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Yeah, I won't touch that one with a 10' pole!! We don't even discuss that under my own roof here at the shop..

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If indeed the thermostat is the bottleneck in the flow, then putting a hi-flow thermostat would help cooling. We have been so focused on the opening temp of the 160 def thermostat that maybe instead it's a higher flowing thermostat, which would help cooling. A visual comparison should make it relatively clear if that is the case.

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Isn't there a thread of Porsche developing an oil that can be used as coolant to solve the intermix problem . Another off topic statement... My choice of oil is whimsical and at the last minute...if I'm feeling 0W40 or 15W50...it varies, and isn't dependent on my mood. Sometimes I play middle ground and put a little of one and a little of the other.

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Even with unrestricted flow without the thermostat will not reduce coolant temps anywhere near 20F from target. Doesn't anyone wonder why their claims are so vague? Cooler temps? What does that mean? Under what conditions? What are the temps? Prevent thermal shock? That is the funniest claim. The fact is, I drive, what is probably the highest compression 3.4 996 on the road, making the engine quite a heat producer. With the factory thermostat, I have no problem maintaining 195F coolant temps. You just modify when the high speed fans come on. The thermostat has nothing to do with the amount of heat your engine produces. You willl not measurably reduce coolant temps without increasing the effciency of the radiators. More airflow is one way to do that.

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we will find out in a sop test soon And: nobody ever said that a t-stat would affect the amount of "heat the engine produces". I helps dissipate that heat...

Ok, I never have tracked my 996 and forgot how the 996 suffers from running hot on the track in longer sessions. So, a lower temp t-stat will most likely not help on a track by itself. Will a 3rd radiator with a cooler t-stat help on the track? Its to be determined. Will the lower temp. t-stat lower the coolant temp on the street? If you run an external t-stat and relay for your cooling fans (~$40), there's a good possibility it will work to lower coolant temps. Will it sustain on the street, meaning, will it keep the coolant temp down on long commutes? That is to be determined. No one here has done it except possibly Raby. Dont know the specifics of his test.

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The fact you can maintain these temps with a heat pump on your engine says there is headroom for lower temps on N/A cars. I know the Vortech and Intercooler get heat soak, Ive owned them both. They get scolding hot on the street! Your car is pumping hot air into the motor and only gets worse the longer you drive. Water-to-air or air-to-air intercoolers all get heat soak and Im sure you know this to be true. So, what I am saying is I dont think your data represents the rest of the N/A 996 board IMHO.

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No heat soak here.

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All those have already been determined. The only way you will reduce your engine temps and sustain them lower is to improve the cooling provided by the radiators. Improving airflow is the easiest way to do this. Thermostat will have little or no effect, one way or another. Those who have done so have testified to the dramitic drop and stability of the engine temperatures. Modifying the fan relays have been done far longer than you have been a member on this forum. Get with the program

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You're joking, right? You're saying your Vortech doesnt heat up and the aftercooler doesnt either after driving? If it doesnt, Vortech and the water-to-air intercooler/aftercoolers have made some leaps and bounds since I owned one 5 years ago. I know you've even said you run higher than 6 pounds of boost. Jim, we are blessed with your "cooling fan modifcation" and thank you. Im glad you took what we have been doing for years to other cars and applying it to the 996. I dont own a 996 anymore btw.....

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Someone should conduct an experiment by removing the t-stat from the t-stat housing and then reinstall the housing. My estimate is that the car will run noticebly cooler, but warm up maybe 5 minutes later. No - don;t put in a 'washer' - just let it eat and see what happens. Cooler operating engine...keep in mind the aux fans don;t come on until 200 degrees or more. Your aux fans will probably NEVER come on.

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You obviously have not be reading this thread. I have already removed the thermostat. I have already reported on what happens. The fans come on at 200F and high speed at 215F. Fans will always be on when AC is on. Edited to put fan speed activation temps.

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Something that heats up (which all things producing energy do) does not define heat soak. Heat soak is defined as the equalization of temperature throughout something of mass. So, technically, every piece of mass on your car, when sitting in the garage not running will eventually be heat soaked. In real world applications heat soak is a range of temperatures and is measured in degrees. Heat soak in the automotive world also refers to the temperature of a mass, gas or liquid that is at a level that is not effected by outside cooling pressures. Simply because the coolant heated by the engine enters the radiator at 250F does not meet the definition of heat soak if the effects of the air passing through the radiator cools the air down, and allowing cooler coolant to feed back to the engine. An aftercooler is not considered heat soaked if the temperature of the air entering the cooler is substantially cooled passing through it. So, I'll state again. No heat soak problems here.

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Ok great - can you then quickly find and repost your comment on running without a t-stat I must have overlooked it. Also - can you copy and post the Porsche technical data for the fans and t-stat??? You are pretty definitive on the googled info regarding car engine cooling - but I want to see the Porsche technical data. Lot of passion - less so on data, stimulating - yes.

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Already been posted.

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Ok, Ive been around dozens of Vortechs from the tiny A-trims of the earliest to the Y-trims. The volute gets just as hot as the transmission after a while of driving.

FYI. Just took the 996 on a trip to Vegas, outside temp was 110 degrees all the way. First time I ever saw my coolant temperature reached 220 degrees!!! That was the highest coolant temperature I ever saw from my 996. Even just at highway crusing at 80 mph the coolant temp stayed at around 204 degrees. Normally, the coolant temp stays at around 193 here in LA.

Robin, when is the last time you cleaned out your rads in the front? There is some serious crap that builds up in there and can hamper cooling. I find it odd that you got that hot while cruising at highway speeds with good airflow. I lived in LV for 4 years and never saw those temps. I was also very vigilant about cleaning out the rads.

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I did clean out the radiator last year by removing the bumper and removing the radiator bracket etc. Did notice the engine ran cooler, but can't imagine that the radiator is clogged up again.

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...I am still planning to conduct an empirical test of the German 160 degree stat - too bad I don;t have it right now - it's 100 degrees here (almost)

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Good point. Then I'm stumped

subscribed, pass the popcorn.

Why did I just spend all this time reading five pages. I'm just going to add some Water Wetter to my car.

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By the way, I'd still like to understand how in the world a car can run cooler with a 160 stat versus a 180 when they are both open at 180??? Of course if you can never reaches 180 then sure, that makes sense but we all know these cars run hotter than 180

[Image-only post; no author-written text. Original image references:] https://rennlist.com/forums/graemlins/banghead.gif

Does anyone know for sure if Water Wetter is approved for the Porsche coolant? I've always used it on past cars, but not in the 996.

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The same way even a Chevy Impalla SS or any other car will.

I don't follow Marlon but something tells you will.

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Anytime you put a cooler thermostat in any water cooled car it will run cooler. I can't explain it, but it works. Always has for me in ANY car I have ever done it on. My old 340 Dodge Challengers, hot-rod 383 Plymouth Fury - you name it, it works. Out 95' SS Impalla ran SO cold in fact, that I had to install the stock thermostat in the Winter in order for the car get any meaningful heat in the cabin. Ran better - in fact the cooler operating temp allowed us to run a computer program that dialed in a wee-little bit more timing advance, but had to run hi-octane with that computer mod or it would ping a litlle under load. Talk about a 4k pound beast! Cooler t-stat WITHOUT the computer mod simply resulted in a much cooler running engine. It works - gotta' work on this car too. IN fact, if you care, simply go to Jake Raby's web site and read up on it. He's a pretty well respected 996 engine guru and they say it works too. But like my cheap and effective SB mod - a lot of folks will remain to be '911 antibodies' that will doggedly insist these mods don't work - why? Because they are cheap and most folks feel that you gotta' spend $2.5K or more in order to make a difference. Hope that spun a couple antibodies up

Ok for all of your water pumper experts... sorry been an air cooled guy for the last 13 years, with the 996 I just get in and drive and don't want to touch it at all. So, this is what I have been experiencing with my 996. What do you guys think might be the issue? The coolant temp. climbs quickly whenever I am stuck in traffic, on a 80 degree day it can go as high as 212F. And once car is moving the temp goes back down slowly, takes a lot longer to reach the 193 normal temp than before. The warm up time is about the same, still takes me about the same exact spot everymorning before it reaches 193F. I cleaned the radiator by taking the bumper off last year, so I know it is not debris related. Water pump replaced about two years ago. I don't loose any coolant, the reservoir keeps pretty good level. My thoughts were: (1) Thermostate not opening all the way, restricted (2). Bad water pump? I did notice dried white residues around the pump area, but no wetness spots or visible drips and no noise. Any ideas?

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What Dell said is fact both in science and in practice. Therefore, your assumptions are wrong. A 160F thermostat WILL NOT substantially reduce coolant temps lower than the targeted temperature of 194F with all else being equal.

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I've noticed that the 996 temps tend to climb up towards the 200-degree range in stop & go traffic on a HOT day. When I discussed it with Raby he indicates that a 160 degree stat will result in cooler temps WHILE DRIVING, but bumper-2-bumper the temps will still creep up, but moving with air exchange occurring over the radiators will result in a temp decrease. I would try a new stat first - go stock temp if desired?! Maybe the stat is not opening all the way??? Is the water pump co-located with the t-stat??? If so replace them both maybe. I have owned aircooled 911's since the mid-80's and this is my first foray into the water-baby arena. I DO intend to replace the stock-stat with the 160 degree German one - soon. My guess is that if one could competely remove the stat the car would run about 180 all day Just a SWAG!!!

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Antibodies unite! You probably think the earth is flat and the tooth fairy stops by every now and then. Yes - there is a Santa Claus tho My assumptions are correct sir. I can sense your heart rate increasing - your blood pressure is creeping up - that vein on the side of your head is pulsing - a slight dampening of your brow is occurring - and your wife (or 'partner') is going to ask you "what's wrong honee..." in a few minutes. Stop now before you blow a gasket. RElax - breathe deep...envision tranquility and calm...

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Your car will NOT run at 180F at any time, in any conditions with or without a thermostat. You seem to think these engine's don't produce any heat.

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Air flow. Increase it and you will be cooler.

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Aue contraier mein fraier - these poorly designed engines produce a lot of heat. Proper engineering and a pragmatic thought process going into the overall engine heat management design would have resulted in less drama. The Deutchers love to design stuff to look good on the drawing board, ummm on second thought, having said that - the V-1 and V-2 were engineering marvels and well as the ME-262, synthetic oil and few other truly groundbreaking engineering breakthroughs - gotta' love them. Anyway, the hot coolant bottle-necks in a crappily designed coolant heat management system. A cooler T-stat will allow the a freer-flowing heat management profile in spite of the rest of the quirky coolant system. Running w/o a -stat might actually make the engine run TOO cold, maybe, sort of, kinda - well, almost???

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Are you willing to bet the cost of a new 997 that removing the thermostat will allow you to run at 180F ? I'll take the other side of the bet. Let me know and I'll make the arrangements.

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Nahhhh - the only sure bet is death and health care reform or, dying from health care reform or something like that. Anyway I'll go with the 160 first. BTW: can you actually remove the t-stat from the housing??? I'm tempted to try it - but will probably go with the 160 first since we are so close to cool WX. I do think that removing the stat will allow the car to run at highway speeds with the needle at the 180 mark all day.

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The only problems tho, is that the 180 mark on the gauge is around 190F.

FWIW, I have a Scanguage II tool installed on my 996, so I know the exact temp. of my coolant real time. What does the fan over the engine lid do? When does it kick in? How do I know if it is even working?

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Dooo - hhh!!! Hmmmm - it's becoming clearer now

I'm going to grab some popcorn and just sit back and watch now since nobody has shown me how two cars (all else being equal) with temps 180+ would have one run cooler with a 160stat. The "I just know it works" thoery doesn't work for me. I mean seriously, can somebody: 1. Show me empirical proof through scientific testing following strict scientific method procedures? 2. Explain how fluid cooling in the 160stat car running over 180 defies physics. If you can show me that, then you have a believer in me.

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I dont think anyone claimed that all you do is change the t-stat and a 996 runs cooler. Of course you have to match the temp of the the fans coming on with the t-stat. Has anyone ran a: 1. 3rd radiator 2. cooler t-stat 3. and had the fans come on at the same temp as the t-stat.... ....while being in a naturally aspirated 996? Until this is done, I agree, we dont have proof. On some other cars, it has worked.

Actually they have. And yes, I totally agree, we don't have proof.

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Already done it. Only increased airflow will make coolant cooler. Remove AC condensrrs and/or change bumpers, and/or turn on fans.

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Jim, I thought you said you removed the t-stat completely? In that case, #2 has not been done and tested. We both know removing the t-stat and running a cooler one are 2 different things.

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I also ran with a permanently opened thermostat. No change. Also ran with thermostat notched on the side. No Change.

I put a larger oil cooler in my 986 and I run cooler at the track (as indicated by the dashboard gauge and the gauge hidden in the radio) than I previously ran on very hot days. It's not scientific, as no two "hot" days will be exactly the same temp and I didn't measure ambient air temps pre and post modification, but from my loose observations the car does run a little cooler (5-10 degrees) post mod. I have not noticed any difference during street driving (and my thermostat and radiators are stock).

I think I may have a "lazy" thermostat. I noticed that in the morning once the car is warmed up to the "happy" 193F, it dips back down to 190 and then back up to 193 again. Which is something I have never seen before. So I am picturing the thermostat being open too long once it reached 193F, and didn't want to close.

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Was this with the supercharger?

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NA and SC'd. 3.4 and 3.6 and GT3.

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Was a 3rd radiator used?

Only on the 3.6. But that would make absolutely no difference since the test was apples to apples.

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So, 3.6 with a 3rd radiator, hollow t-stat used as essentially an orifice, and your fan mod. What temps did it run?

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The tests were all related to the particular car. Temps with and without and propped open. Rather than the thousand questions and since you are so skeptical, just do the test yourself. Not difficult at all. Conditions were constant with no change in stock fan operation.

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So of course all the variables like I initially stated have not been tested. Of course if you dont turn the fans on sooner it will get hot. Sorry, Im done and wont say more.

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Remember that this is a debate about whether changing to a lower opening thermostat will reduce coolant temperatures. No other changes to engine or conditions. Obviously there are many mods that can be done to reduce temperatures, but a thermostat change alone will not do it.

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Yes, and that is why I hate debates on here. Points tend to be missed and cause disputes.

Cooler t-stat or no t-stat results in cooler running car. I've done it several times on American V8's. And sometimes they run too cool. Why - because their (latent) heat exchange system capacity generally overmatches their generated heat (hot water). The cooler t-stat or no t-stat allows more water to be "heat exchanged" during during a given time - hence a cooler running car - too simple to understand, huh!? Now the 996 has a pretty well overloaded heat exchanger system as it is, it was designed to operate at the very edge of it's margin to for tangible cooling - why? Because that's the way Porsche designs anything - just ask all the air cooled guys - and I have owned a bunch of them. So the 160 degree stat on the 996 results in a smaller degree of improvement. Why - becasue the coolant system on the 996 just absolutely sucks. On the ottobahn at speed it will work ok, but for U.S. driving or tracking (oooops - remember that the 996 was not built to be tracked - shame on you if you overheat the darn thing wihile DE'ing). So - cooler or NO stat = cooler running car if your radiator is up to it. Yes - the 996 'radiators' are not really up to it - even with the aux fans, they simply come on TOO damn late. Too bad we can reflash the cptr to provide for them to come on 20 degreee sooner. I think the cars would live longer if they did.

See if this logic makes sense. No thermostat also means longer warm up time, which is bad for emission and puts more wear and tear on the engine because now it take longer for the oil temperature to reach the proper viscousity for protection. So what we really need is a thermostat that allows the car to warm up as quickly as possible, but once warmed up to fully open to allow as much cooling as possible. Make sense? Time for a electronic servo controlled thermostat?

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True - but I don't think a slow warmup is going to actually result in a shorter engine life. Maybe someone can comment on the 2ndary air pump that comes on following a COLD start. Is it's run time based on a 'clock' or engine temp??? Good idea on the electronic t-stat maybe.

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The specs. on running the SAI pump is different for all cars, but I am pretty sure the run time is based on engine coolant temp, and possible from the 2nd 02 voltage output. I am a true believer or engine wear from cold oil, that's why I always cringe when my wife gets in her car and floors the gas and take off right after a cold start.

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Well - think of it this way: when the engine is started cold, the engine itself (pistons, cylinders, rings, valves, rods, etc) are going to warm up in about 15 seconds. The coolant will take a little longer, but you don;t really care about the'coolant' early in the initial start cycle if you use your brain when driving away and excercise reason. Wives can be taught - but usually at the expense of a tangible 'treat' - carat on a stick so to speak.

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It takes alot longer than 15 seconds for those components to reach proper temperatures. Until that time, all you have is hot spots which is the most vulnerable time for the engine.

Marlon, if we have two equal taps and you open yours first, does that mean you are running more water? It surprises me that Jake is making such statements... I thought his IMS bearing developments and were great, but this 20 degree drop claim is baffling. I am more scared of micro-cracks (leading to things like a D chunk) from running a cold engine, than running an engine at 196F. at 193 (make that even 200- it is fine)

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I was schooled on always providing a rapid double-tap to the torso followed by an accurate head shot - works great. Resultant flow will depend on after-action enemy orientation with the ground. I recommend that you articulate your bafflement directly to Jake. I can help you with double tap training though

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You might have gotten one head shot too many and damage the brain t-stat for intelligence flow- but you remind me of my marcial art fighting days If you do the mod, please keep us posted

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Will do - this has been quite an exciting thread...

Wow...this thread is still going on? Let's get Porsche to switch back to air cooled...that should end this .

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I think it is winding down...lots of views and hits tho.

Ok, I'll throw in another $1.00. Technically probably both sides are right here. In conditions in which the thermostat is cycling to maintain proper operating temperature, the net result of a lower temperature themostat will be a lower coolant temperature and POSSIBLY slightly more horsepower. Theoretically, in the righ conditions (a cold day), the coolant temp might average 10-20 degrees lower with the lower temp thermostat. In conditions in which the thermostat is wide open such as a hot day, the factor controlling coolant temperature is not the thermostat, but the radiators and airflow over them. If it is hot outside and you are running the car hard enough to get over 200 deg, then the low temp thermostat will have zero effect. Hope that helps extinguish the fire and not add fuel to it.

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Thanks Ed, that makes a lot more sense.

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Cool!!! or hot!? Great though in any case!!! $1.00 well spent.

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As I explained above, the lower openinng thermostat being discussed WILL NOT lower coolant temps 10 - 20F. It does nothing to increase flow anymore than the stock thermostat. This has all been tested, even in sub zero temperatures. Increased coolant flow and/or air past the radiators is the only way to measurably reduce your temperatures. Theory is only imporatant when facts are not known.

That is where you are right and wrong. If the conditions are so that the 185 deg thermostat is cycling, the 160 deg may be fully open. While this in of itself will not change the coolant temp, it WILL increase the flow to the radiators which will in turn allow them to dissapate more heat. If the coolant temp is 175 degreesn, the 185 deg themrmostat is closed, the flow is 0 where as the 160 degree would be 50% open and there would be flow. In the grand scheme of things, the difference would be very minimal and only under certain conditions. The grand total benefit in terms of power over time would probably be 1% of 1%. This probably will not matter to any of us, but does in something like the 24 hours of LeMans and explains why the 997RSR has an optional lower temp thermostat, although I do not know the specific temperatures for the standard or endurance thermostats.

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You're talking "if's" and there are no ifs. It has already been tested. If a lower opening thermostat can increase flow, it may aid in cooling, but the thermostat we are discussing does not increase flow. BTW: You are either right OR wrong. You cannot be both.

It does between 160 degrees where it starts to open and 200 or so when it would be fully open and the 185 deg thermostat is at 99%.

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Your engine cannot run at 185F even without a thermostat, so, what's your point?

We are not talking about engine temperatures, we are talking about coolant tems.

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So am I. In all water cooled engines, engine temperature is coolant temperature.

Put a Durametric, ScanGuage or PET on the car and read the coolant temp before you run the car, it will be approx. the ambient temp. Hopefully below 185 or you won't be doing well. Once you start the car, it will increase until the thermostat begins to open at 160 or 185 depending. So yes, there are times it can be below 185 deg. This can be reproduced by getting the car nice and hot with high load and low radiator heat transfer and then swithcing to low load and high radiator transfer and the engine will cool and as it gets below 200, the stock thermostat would start to contract to restrict the flow and keep it from going too low. The lower temp thermostat would stay open longer and allow the engine to get cooler. Again, it's basically all irrelevant unless you are fighting for that last 1 second in a 4 hour race. On a street car, it's all moot. But as we have all seen in races, after an hour or evem 24, the difference between winning an losing can be 1 second. That's where this matters. And on a summer day in SoCal, it would all be irrelevant anyway and the high heat production and low cooling ability will probably keep itall above the thermostat's control anyway and the modulation in controlled by the DME and the 3 fans.

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Once your coolant reaches 186, you will never, ever see 185 again even in sub zero temperatures EVEN WITHOUT A THERMOSTAT, while running an otherwise stock cooling system and stock bumper. Remove your thermostat and give it a try.

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You would be right if one kept the stock heat exchangers. More capacity in the heat exchange could drive the coolant so low the engine might not function. The 996 is hamstrung by a marginal coolant system. Maybe the MK2 and 997 got uprated heat exchangers and/or a new algorithm to turn the fans on EARLIER.

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Well, since I specifically stated stock cooling system and stock bumper I am right....as usual. The 997 has the same problems although they did lower the temp gauge to give you a cooler feeling.

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Partially - The car would probably run significantly lower coolant temp at subzero operating conditions. That's why 18-wheelers have special curtains on the front of their radiators in the winter months which even only ocassionally see "sub zero" temps. If they did not run with the curtains to BLOCK OUT some of the COLD air, the truck would not run. Why you ask - because the coolant is TOO cold. Same thing would happen with the 996 is sub zero temps.

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Read the thread and you'll see I already addressed sub zero operation and coolant temp. By the way, I have a CDL Class A license so am slightly familiar with the operation of over the road trucks.

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OK driver, I still give you partial credit even though you know something about trucks - but that is all. However, your inputs, are based on an emotional reaction to a subject on which you can claim no scholarship nor accreditation. Make for good soap opera though.

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No accreditation. Just the facts to back me up. Let me know when you get your car to maintian coolant temps below 185F on your stock exhaust.

99, you are correct that with a 185 degree thermostat, you will never be able to get below 185 in the engine side of the coolant system. And 160 with a 160 thermostat. The arguement here is that with a 160 thermostat, under certain circumstances you can get below 185.

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You will not get below 185F WITHOUT a thermostat. Why is that so hard to understand? You could install a ZERO Degree thermostat and you will not run below 185.

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Admittedly with the stock *crap* cooling system - with their heat exchangers working at the very hairy edge of puny efficiency together with fans programmed to come on as late as they do, yes, the system might not ever see "below 185" during normal operating conditions, If someone could come out with a set of super duty HIGH efficiency heat exchangers and a computer program to kick the fans on 15 or so degree earlier, I think we'd all be cooking with gas. Engines would be happy, I'd be happy - hell, the world would be happy. When I get around to acquirng the 160 deg stat, I want to also have access to the system that can be plugged into the OBDII port and monitor temps real-time, not on the gage BTW: how about some of that 1/2" thick, aluminized insulation to stick between the muffler cans and the engine - I think you can get that stuff at marine parts shops.

Ok, iyou cannot make an arbitrary statment like that. While it is probably 99% accurate, the conditions can exist where the system could cool to under 185 degrees. Lets play with the numbers... It 30 deg F outside. A car traveling down the road at 50 mph and getting 25 mpg, sounds realistic for a Porsche on the highway. That means it is buring 2 gph of gasoline. Gasoline has 125k BTU/ gal so the total energy available during that hour is 25k btu. A typical gas engine is around 50% efficient, that means 50% goes to mechanical power and 50% to heat. So we are at 125k btu. Now is where it will get a bit grey. How much heat goes into the coolant and how much is lost through other systems (oil cooler, exhaust, radiat, heater core). The heater core alone can pull 25k but, so lets say we end up with 80k btu into the coolant. Now there are two ways to look at this... One is by degree delta in the cooling system. A BTU is the energy it takes to raise 1lb of water 1 degree F. The cooling system on a car is basically glycol these days. Gycol takes 1.6 btu to raiuse 1 degree F. The 996 cooling system takes about 22 litres of coolant which at 2.28 lbs / liter is around 50lbs. Therefore we can raise the coolant temp by 1000 degrees over the hour, that is 16 deg / miniute. So, that leaves the question of can the radiators drop the coolant temperature by 16 deg / min or more (would need more to actually lower the temp) with 50mph 40 deg air flowing through them. As I do not have the thermal transfer numbers from the radiator, we kinda get jambed up here. Or by cooling system capability. Doing the same math, the cooling system on my car (with thrid radiator) can keep the car from over heating on a 90 degree day (actually runs around 190) on the track with me burning about 16-17 gph. Ballpark that is a million BTU per hour it needs to dissapate. As above 80% of that heat goes into the coolant, that is 800k btu dissapated per hour or 10x what we are producing in the scenario above. How much does the thrid radiator add, even if it doubles the capacity, the system could easily reduce cooling temp in the engine under the right conditions. As you know, with any thermostat, it will begin to close as it comes close to its temperature rating, therby reducing coolant flow and reducing the ability of the radiator to dissapate heat. This will keep the coolant temperature stable. This is why they are there in the first place. So, if you have a 185 deg thermostat, you will never get below 185, but with a 160, you could get below 185. Without a thermostat, there is a minimum number that it could not get below, this is where the efficieny of the radiators to dissapate heat (based on delta of coolant temp to air temp) crosses the heat production of the engine. Will this scenario ever exactly play out? 1% and if so, would it matter for the driver having the cooler thermostat, so little it is not worth the money to change it. Regardless, technically it is possible.

Why do you want to run below 185? The engine needs to run I'm guess at or near that temp to be efficient, make power, and burn off the water that condenses in the oil. You want more capacity - install the C4S/TT bumper and radiators. I don't understand why this is such a big deal?

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me neither. cars dont' run well at low temp. In fact the Carnot efficiency is defined by the temperature difference. The larger the difference, the higher the efficiency. Its the materials that can't handle it.

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It's not a big deal really - just spirited discussion amongst armchair experts. Probably no bigger of a deal to go from stock, 17" rims to 18" or 19" rims. Maybe even lesser of a deal than 45-hundred bucks for some bigger rims & tires or louder exhaust pipes - same difference, just that different folks like to float their boats in different oceans - seeing as how the 996 crowd is pretty much stuck with the same 'boat'. Heck - we-eeze jus 'rastlin'...

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Sometimes you have to simply accept reality and let go of theories.

Last year the LN Engineering low temp thermostat was tested in -27 temperatures in Chicago. The test vehicle was driven from Chicago to my facility and the entire time it never saw a temperature above freezing. Cabin temperatures did not suffer and the coolant temp hovered at 176F for the majority of the trip. I have removed the thermostat from the cooling system on more than one occasion and found the coolant temps to skyrocket as the coolant passes through the radiators too quickly to thoroughly cool.. It also passes through the engine too quickly to remove heat. In the engine conversion world (for all sort of engines and cars) the selection of thermostats and radiators is quite a chore simply because of issues like this.. (Even though its not related to the M96 engine) I appreciate the knowledge base of the posters in this thread, but I feel that a lot of the negative chatter I have heard here would not exist had the posters actually experienced the low temp thermostat back to back in their vehicle. When I began the testing of this unit for LN Engineering I was also skeptical that the unit would make any difference at all, and I could not have been more wrong..(thats what happens when assumptions are made prior to actually experiencing the development). I own a 98 Boxster and a 99/ 911 as well. Both of these vehicles run the thermostat and both dropped a solid 15 degrees on the data logger when the low temp unit was applied.. The stock gauge has crappy resolution and while it does show some variations in temp, they are not as great as what I have gathered with my race-Technology DL-2 and DASH 2 units in both cars. (on the street and track) The numbers game, equations and calculations are great, but practical application experience has proven this development "worthy" to my engine program and therefore I employ this unit in EVERY engine that I create as standard equipment. Because of this I can increase displacement of a 3.4 engine by 400ccs, make 70HP more than stock and the engine stills runs cooler than it did in 100% bone stock form. Just try one and see what you experience... Nothing else is fair. Please don't close your mind, thats how you get passed.

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That temperature WAS NOT acheived on a stock 996 with no other changes than the thermostat.

which change are you referring to?

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Jake - I will order one asap, along with your oil drain plug and filter kit. Will call it in Monday. mar

I'll probably end up answering.. My General Manager is in the Hospital :-( Do us a favor before the install of the lo temp unit... Pay attention to the temps you see with your engine in different ambient conditions.. Maybe make a simple log of before and after, especially if you drive the same roads and speeds often (Like I do on my 83 mile all back road commute).. We need your experiences when threads like this one pop up, even though people that haven't experienced the unit first hand will still argue with the validity of your experiences.. And if you don't see enough of a reduction in engine temps to justify the expenditure, just return it and I'll give you your money back. No questions asked. No arguments. Talk to you Monday (try to call me in the early morning if possible, I'll be in assembly after Noon). if I miss you I'll return your call between 1800-1930 on Monday evening EST. I'd also like to clarify a point made in my earlier post. I basically stated that the lo temp thermostat was allowing us to build engines 400ccs larger than stock alone... That is incorrect. what I meant to communicate is the fact that we create engines that are 400ccs larger than stock that run the same temp as they did (or less) in the same car with a stock thermostat, even while making 70HP more.. Thats not all related to the thermostat, its part of the winning combination, however.

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Maybe you would like to share with us what date you drove your 996 test vehicle in Chicago in -27F. Now I understand why you can claim impossible low coolant temperatures. Your sensors are wrong.

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sounds great - !!! Do I need to order any gaskets or sealant?

99 Porsche 911, The car that was driven in those temps was LN Engineering's '99 Boxster.. It was January of 2009 during the extreme cold snap when I believe it got as extreme as -34... Charles was the one that experienced it, so maybe he'll chime in. The sensors are not wrong, we have logged OBDII coolant temps as well as used two other channels of the data logger in a couple of different locations in the cooling system to quantify the numbers.. And believe it or not they are even fairly close to the stock gauge- its just slow to respond. Why don't you buy a unit and install it, then you can offer first hand experiences, not based on equations or assumptions.. Just a thought. Marlon, no sealant needed.. The thermostat gasket comes with the unit free of charge.. ;-0

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The record low temperature in Chicago this year was -18F. I suggest you recalibrate your gauges before making such exaggerated claims.

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shhhh - - your scaring the children! I'm going to gueanie pig the 160 deg stat. Anything else other than oil drain and filter to update while under there???

I stand corrected, LN Engineering is located in Momence Il, I really don't care what their record temperature was this year, but I do know that charles was driving purposely in the cold temperatures (even late at night/ early in the morning) to gather info and do cold weather testing.. Even if it was ONLY -18F, thats should certainly still be "cold enough" to make the point that cabin temps did not suffer with the lo temp unit installed. I apologize for not taking the time to gather weather information before making my post, I should have known that you'd do exactly what you did. I promise next time to be more prepared. And perhaps you should actually employ the lo temperature thermostat and experience it yourself before stating that it does not offer any cooling benefit at all. Any reason why you seem to be so moody and abrasive?? I'd think if you were so serious about making your point that you'd be motivated enough to have already bought a unit just to prove it wrong.. How many thermostats have you installed personally? Just wondering.

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Was this the same test or just another incorrect ambient temperature?

Nope, it was more than likely incorrect.. Now, I answered your question and gave you the answers you were looking for, so I'd appreciate the same from you. If you were sent a thermostat for free would you install it personally???

Jake raced my new 3.4 at Laguna last weekend and saw temps up to 215 with a 3rd radiator. It was only 78 or so outside. That's about what my 2.5 and 2.7 Boxster motors ran. Next up is Cal Speedway in 3 weeks where I expect temps in the mid 90's. How much difference would you expect from your stat in those conditions?

Probably about 10 degrees less based on what we saw with my '98 at Road Atlanta a few weeks in similar conditions, even without a 3rd radiator and putting out 200 RWHP with the ECU flashed very close to the edge (lots of timing!) and our cams. All weekend the engine ran at 200F. I'll send you one and if you like it you can offer us some data from the track and then pay for the unit if you want to keep it.. Otherwise I'll use it here at the shop when you return it. As you can see, I need lots of people willing to be vocal about what they experience it.. I'd not be so willing to do this if I didn't have a lot of confidence in what you'll experience.. I have seen it too many times! (BTW- we need to talk offline, I have a "silver bullet" that needs to be employed at a certain event in your area)

Quotes source post: 6859549

I know many here consider this a social networking forum and participate in a love fest with each other even when they come across blatantly deceptive information. I call a spade a spade. Let�s see�in this thread alone, a 996 thread, you mislead us into thinking that you have tested a 996 with the new thermostat, yet the vehicle was NOT a 996. You didn�t bother stating that fact until I challenged you. You also stated the vehicle was tested in temperatures lower than have ever been recorded in Chicago, but you expect us to believe your other data.. I can only imagine what else you have exaggerated about on this forum. As far as I am concerned, any credibility you might have had is lost on me because of your misleading statements. So, it appears that I am the only one to offer any test results of a 160 thermostat in a 996, 3.4 and 3.6 and it does not live up to claims. However, Ln�s marketing doesn�t even make any claim to lower coolant temperatures, only increase power and make the engine last longer, so it gives you an out. Nothing but a gimmick from my experience. LN Engineering offers a 160F low temperature thermostat for 986 as well as 996 models and replaces the factory 186F thermostat and housing, Porsche part numbers 996 106 125 52 (53). Also fits 987 and 997 models to 2008. Price includes new oe Wahler thermostat housing and custom low temperature thermostat manufactured in Germany. Provides increased power increasing power while ensuring consistent performance and extending engine-component longevity.

To clarify. I HAVE tested the units in my personal Boxster and my 996. Both cars have them installed right now and are sitting in my Garage. I have two 3.6 engines equipped with the units at my shop right now, one started as a 3.2 for a 00 Boxster S that made 290 RWHP and the other started life as a 3.4 for a 996, it hasn't hit my dyno yet, but will Monday. I never said that **I** did the cold weather testing, because I didn't.. and I also have not completed the hot weather testing, because our temperatures this year were no where near what they were for the last couple of years. I did gather some data, but not what I was looking for. You still haven't answered any of m questions, so I suppose it's acceptable for me to be "challenged" because I am a Vendor, but you have an "out" because you are just an Enthusiast? While I may have lost my credibility because I didn't do a Google search prior to stating a certain temperature down to .3 degrees, but I maintain my integrity. Now please answer my questions or don't "challenge" me again... Install the unit, prove that it doesn't work or please do not engage in negative statements concerning it.

Quotes source post: 6859710

If you had read my posts, you would have known that I have already tested the unit. Installing the LN thermostat in an otherwise stock 996 does nothing to reduce coolant temperatures. It does nothing to improve flow, either. I can't be more plain than that.

I did not read all of your posts, I suppose I should have. So you saw no differences at all in your car?? Why didn't you state this way earlier in our discussion this evening? We'll agree to disagree and I won't bother challenging your testing procedures or even ask if you measured the coolant temps in any way other than using the stock gauge. I also won't challenge your ability to correctly bleed the cooling system for absolute results.. Because you are the first person out of hundreds that has stated this and I learned long ago that a solid 10% of the following is going to find something wrong with anything we develop and are incapable of being pleased. So I guess that means we are doing better than average. I'd expect that with another year or so of sales under our belt all over the world that by this time next year it won't matter what data we have collected, users will be vocal enough with positive experiences to recommend this component to their friends here online. Good night, have a great rest of the weekend..

Quotes source post: 6859731

Didn't think you would answer. Hey 1999, what do you do for a living please?

This is an awfully deep pool -- aww what the heck -- let's dive in and see whether we can swim. Many years ago when I was a trainee automotive technician I was taught the following: The vehicle manufacturer designs a thermostat to suit the thermodynamics of the particular motor vehicle including the efficiency/performance of the radiator and the engine design and so on -- so as to keep the engine at the designer's optimum temperature. If everything is working okay the thermostat should be able to adjust to suit ambient temperatures and driving speeds and different loads so as to keep the engine running more or less at the designer's optimum temperature. In some engines (we were told almost all engines) if you remove the thermostat altogether the engine will run very cold because the water goes around so fast that it never gets time to heat up meaning that most vehicles have radiator capacity beyond the need of the engine. The thermostat is nothing more than an adjustable choke to try and keep the engine temperature at the designer's optimum temperature. In this thread some people say there is a temperature that is more desirable than the engine designer's optimum temperature. Jake Raby seems to be saying that he would prefer to see a lower temperature -- he says his experience with water cooled Porsche engines leads him to believe that the designer's optimum temperature is a bit too high. Jake Raby may well be correct in what he says but I don't have anything by way of evidence to prove that but I can say that modern engines are designed to run a bit hotter than engines of previous decades so as to promote lower emissions (and if I'm wrong on this please let me know). So on one hand we can say Jake Raby thinks it's a good idea to lower engine temperatures a little too perhaps try and get a bit more performance at the expense of slightly higher emissions and also to try and get a lower engine failure rate. The question then is quite simply -- can a thermostat be used to just a little bit lower than the average operating temperature of a 996 engine? And here -- for the purpose of this thread -- we have to use a dose of common sense -- as follows -- if the Porsche engine design department has used a thermostat that tries to maintain temperature (aka water flow) to achieve operating temperature 5 on a scale of 1 to 10 then you must be able to have a thermostat that will achieve an operating temperature of 4 on that scale and you must be able to have a thermostat that will achieve an operating temperature of 6 on that scale. There will of course be a point where the temperature gets "out of whack" because it is beyond the design capacity of the engine and cooling system -- such as when you remove the thermostat altogether making the engine run very cold or when you put in a blocking plate with say a quarter inch hole in it (aka a superhot thermostat) which would make the engine boil very quickly. So although some people seem to be saying that a colder thermostat can't make an engine run colder I think those people don't have a proper understanding of how thermostats throttle the water flow on an almost constant basis and that opening temperature is simply the temperature when the thermostat opens up and starts its real work of maintaining an acceptable coolant temperature in a wide variety of operating circumstances. The temperature marked on a thermostat is the opening temperature only and is the reference temperature that the automotive technician users to test the thermostat to see whether or not it is opening at the correct temperature. You can have two thermostats with the same opening temperature but with different design characteristics (aka flow potential). So two thermostats with the same opening temperature can end up giving a different operating temperature -- one of them can have a smaller choke (aka hotter) and the other can have a larger choke (aka colder). Truckers use radiator shutters (and most modern designs have are thermostat controlled) so as to reduce the airflow to the radiator because in very cold weather that airflow can stop the truck from ever getting hot enough to run properly. The point that the previous poster seemed to miss is that in such a truck the thermostat still opens at the required temperature because until the thermostat does open very little water leaves the engine meaning very little water gets to the radiator. It is only when the thermostat is open that the radiator shutters come into play because without those radiator shutters the water temperature coming out of the radiator would be too low thereby quickly taking the engine back to a very low temperature which would close the thermostat altogether and not allow the thermostat to operate as it should and stay open and move backwards and forwards within its range throttling the water but not shutting it off altogether. Constructive comment eagerly sought. And finally, If you don't understand that a soap box is both a privilege and a responsibility it's certain that the short step up will see you fall a long way down. Amateurs don't build skyscrapers -- entrepreneurs do. Don't doubt a man just because he's got a financial interest -- remember he's got a profit motive to get it right and that is perhaps a better guarantee than an amateur with an automotive ego motive. Michael Gibney

Quotes source post: 6862897

A couple of comments: First of all, the flow of the coolant in all 996�s was not designed optimally. The water pump and restrictions in the system do not flow the coolant where maximum efficiency of the radiators are achieved. If the system was designed correctly, increasing coolant flow would actually increase coolant temperatures in most cases and not decrease them as is the case in the 996. The 996 engines are designed to operate at a 194F minimum temperature, yet due to coolant flow and insufficient air flow, coolant temperatures regularly reach 215+F just driving around town. Part of the cause is insufficient air flow and the design of the front bumper as well as the placement of the AC evaporators and their size relative to the radiators. Without a thermostat in the system, the 996 engines run slightly cooler around town due to increase coolant flow and coolant temperatures can drop down to slightly less than 190F on the open road, depending on road surface and temperature and wether the AC is running. This is not theory, speculation or anything else but factual information that has been exhaustively tested. The easiest and by far, the most efficient way to decrease your coolant temperatures in the 996 engines and to eliminate the huge swings in engine temperatures is to increase airflow through the radiators. This can most easily be achieved by running the fans during slow driving. An undersized water pump pulley has also shown a slight decrease in temperatures as does keeping the engine compartments cooler than the commonly 150+ F temperatures it reaches driving around town on sunny days. As for your statement: In some engines (we were told almost all engines) if you remove the thermostat altogether the engine will run very cold because the water goes around so fast that it never gets time to heat up meaning that most vehicles have radiator capacity beyond the need of the engine. That is not correct.

and here I am was just going to ask everyone where do I order the cooler thermostat from...

I agree that this is not correct. The fastest way to elevate an engine's temperature is to remove the thermostat altogether. I also agree that an under drive pulley helps to reduce temps.. I have proven this on the street and track with my 996 running a 4" UD pulley that I have been testing. WOW, we agreed on something.. COOL!

Quotes source post: 6864000

Oh thank God, 1999 and Jake are agreeing! There is humanity after all By the way, we run the 4" UD pulley in the spec boxsters

I installed an Inengineering 160 degree thermostat in a 2001 C4. On the highway at greater than 60 reasonably steady state MPH, my temp gauge needle is on the right edge of the 180 degree post. That has not happened before and it is now consistent. When I slow down well under 60 MPH - traffic jam or lots of town stop and start driving - the temp gauge shows that the C4 heats up to where it always did under those conditions - right of the 190 post. I asked the owner of Inengineering why this is so. He replied that for so long as a lot of air is being rammed into the radiators the cooling fluid is flowing through the engine at an earlier temperature than the factory version. Next, I will install the Dakota digital temperature controller and start the fans at a lower temp and start up high speed at a lower temp and let the fans stay on for a programmed period after the car stops if the temp is at a programmed level when I turn the ignition off. Cicerosecundus