Ideal 996 Thermostat temp for Florida???

So, apparently Porsche recommends a 180 degree thermostat for the 3.4... Is that with Central/northern European climates in mind? Engine is out getting IMSB, clutch and such done... should I put in a 180 or 160 degree thermostat?

what did your shop/mechanic recommend?

Definitely a good upgrade. These engines don't do a good job of cooling evenly. So it's the hot spots that don't show up on the coolant temp guage that you are worried about. From Pelican: http://www.pelicanparts.com/techarti...eplacement.htm The factory thermostat starts to open at about 187 degrees F (86 degrees C) and only fully opens at almost 210 degrees F (99 degrees C). This means that the engine needs to get very hot before it starts sending its coolant to the front radiators. For this reason, I recommend installing a low-temperature thermostat in place of the factory one. LN Engineering has developed a thermostat that starts opening at 160 degrees F (71 degrees C) and is fully open at about 180 degrees F (82 degrees C). Lower coolant temperatures translate into lower oil temperatures, and the dyno tests that LN Engineering has performed on the cars with the low-temp thermostat installed have revealed a small increase in horsepower (typically about 5 horsepower). It is my guess that Porsche designed the thermostat to open a bit later in order to help the cars run a bit hotter, which typically helps with emissions testing and the burning off of water out of the oil, which can then lead to longer oil change intervals. Installing the low-temp thermostat is a smart idea for engine longevity--it's available for about $175 from PelicanParts.com.

Quotes source post: 13498621

Use the factory T-stat. If you are worried about engine cooling install a 3rd radiator. Frankly, it doesn't get that hot in Florida. Up until a day or two ago it had reached 100F 6 or 7 days a row here where live in CA. Both cars have the factory T-stat and both run just fine. Both cars have been in much higher ambient temperatures -- from 116F to 119F -- and have not had any problems. That's with over 303K miles on the Boxster and over 145K miles on the Turbo. Remember the oil, 0w-40 or 5w-40, the "40" is the oil's viscosity rating at 212F so the oil is designed to run at what we might consider "hot" but not to the oil.

as soon as the rest of RL wakes up, stand by for a healthy debate about this old/recurring topic

Quotes source post: 13498831

Oh yeah! Almost as good a debate as what type/weight oil should I use...

I installed the 160F Tstat. My Porsche mechanic strongly recommends it on the 996 base don his experience. They can be found for WAY less than $175. I think with the housing I paid around $80. IIRC, the 997 cars have 160F tstats?

Read this document and decide it for yourself. This is the most comprehensive analysis by engineers to date that's in publication I've seen. http://www.hartech.org/images/downlo...0(interim).pdf I'm tired of explaining it.

I found a shiny new 160 detree tstat not terribly far away, it's en route to the shop. My mechanic said that in FL climate, going this route will help reduce chance of heat soak. Sounds pretty much on par with most of what I'm seeing in these responses. Thanks for posting the literature links. Very interesting reading.

I think we should put that link as a sticky.

Quotes source posts: 13498628, 13502372

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

I agree. Especially since on most cars, the thermostat is on the hot side exiting the engine, to the radiator. On the Porsche it is on the cold side, leaving the radiator, mixed with the engine discharge that circulates through the heater core. Makes no engineering sense that the same high temp (185F) is correct for the hot side and the cold side. Read that Hartech article many years ago, and convinced me for sure.

One of the great things about that article is it also explains the corresponding design in the air-cooled and even 944 engines and how they are different than the m96 and why these problems are only unique to the m96 series. Even with the m96, 3.4 and 3.6 are very different too and it explains why the 3.6 is more prone to scoring. It's really great that they share what they found and their methods to support their theories, which I must say make a lot of sense when you put everything together.

I have an RN replacement engine in mine. Those come with the LN lower temp thermostat (as well as Nickies cylinder liners and some other improvements). Previously I was sure a lower temp thermostat would not affect the upper operating temp once the stat was fully open, but I have noticed it's a bit lower according to the guages. Although I can't say for certain it's due to the thermostat vs some other modification(s).

In an absolute sense, you are correct. A full open 165F Tstat passes the exact same amount of coolant as a 185F Tstat. The problem is that under normal driving conditions, the 165F is full open and the 185F is not. SO when you decide to push the engine the hot spots that may (or may not) exist in ones particular engine example, will get too hot before the Tstat sees the increase in temp, and enable potential scoring. The 165F is already at full open and full flow and can prevent the hotspot from ever occurring. When I switched to the 165F Tstat at around 40k miles, I noticed immediately that the indicated temperature on the gauge was a full roughly 12 degrees cooler just cruising down the interstate. During spirited driving it would rise less than it did with the older tstat, but more importantly, once back to normal driving, the 165F unit quickly brought the temp back to it's previous level, indicating that the temperature was under control. The old one used to stay elevated, indicating the cooling rate at the tstats current position was significantly less than the 165F. It was not equally full open. For a few bucks, it is one less contributing factor I have to worry about.

I have an 180 in mine and sits right over the 0 in 180 all the time.

Quotes source post: 13498977

Does the 997 T-Stat fit M96 motors?

Quotes source post: 13499563

Thanks for the link. I dont get this comment" "With this new thermostat – warming up times are almost identical but as the new thermostat reaches a general running temperature of around 82 deg C (180 Deg F) it stays there while the original would continue to rise to 95 to 100 Deg C (203 to 212 Deg F)." My car always run at 180F I liked reading the article. However, Always that I read something like that, coming from a workshop, doesnt matter how experienced they are... always a question comes to my mind: Would you trust more on them than in the Porsche engineers/know how?

Quotes source post: 15551276

My gauge almost always indicates 180F on the dash as well once it is warmed up. But my Snap-On Scanner has proven to me that 180F on the dash = 170F-210F actual temperature. The gauge cannot be trusted.

Quotes source post: 13499563

I'm geeking out on this article, thanks for sharing! Admittedly I am not very far through it, but one of the issues I am seeing is from the increased rod angle on the 3.6 motor due to the longer stroke. Has anybody attempted to use a longer rod and raising the piston pin height in a custom piston to reduce the angle? There are a couple of benefits to doing that over just decreasing the side loading of the piston, you also end up increasing the dwell at BDC allowing more time to fill the cylinder. Would love for somebody like Ahsai or any of the M96 gurus to chime in on this.

Quotes source post: 15551276

As far as the temperature changes are concerned when going from normal to hard driving, the temperature of the metal doesn't change instantaneously. I'm curious about how much time it really takes versus the cooling flowing to where the thermostat opens up. Did they monitor all six cylinder head temperatures? They could simply use an airplane gauge and six spark plug ring temp sensors. There's even a data recording feature built into the gauge. They can also monitor fuel flow and generate a graph of fuel flow (indicating power) along with cylinder head temperatures against time. Here's a typical engine monitor https://www.jpinstruments.com/shop/edm-730-2/

Quotes source post: 15551276

Yes, the Porsche engineers made several mistakes in the design of the m96/97

Quotes source post: 15553689

True but one thing about using the lower temperature thermostat that seems odd is the claim of more horsepower. Why would a lower temperature generate more horsepower? Less head on the water pump? Not to be mean but one thing is for certain, put a Porsche product on the market, claim it adds power and it will sell

Quotes source posts: 15551276, 15551470

The coolant temp gauge indicates the coolant temp sensor reading. The sensor is on the front console (where the red path is in this post) and it measures the coolant that just exited both heads. I think what that sentence in the article refers to is the maximum temperature at some parts of the engine (they put individual temp sensors at different parts of the engine), not the temperature measured by the stock sensor. That would be something fun to discuss with Jake. I'm not sure the stock crank carrier will allow that w/o modifications.

Quotes source post: 15553689

Leaving apart that there is almost no engineering process without certain rate of failure, and of course, the car manufacturing is not one of them, which are those mistakes? I know... the infamous IMS... well, once again... reading this forum it looks like the IMS fails in 100% of the cars or, other way... in the 100% of the cars it will fail yes or yes... and that is far away from the true. There are weak points in the M96 engine?... yes, like in almost all and every automotive market car engine (We can talk about Audi FSI engines, BMW 1.6THP, BMW N47, VW 2.0 TDI, BMW V10, VW W12, etc, etc) But, leaving that debate aside. Can we decide to change design parameters based on the opinion of a workshop further than the Porsche engineering know how? I dont know. Of course, every design can be improved, because all developments must fit a cost/benefit requirement. The 911 is a high performance car, and its cost design parameters are higher than, for instance in a VW golf, allowing better (and more expensive) materials, etc. But of course, you can even find better break pads in the market, or better shock absorbers... but, a piece like a thermostat? Why would be the reason to include the 180F instead the 160F if that is a better solution? Design cost parameters, no. So as engineer, I tend to think that developers find always the best solution for its application. Why the Porsche workshop procedure says: change the RMS, change the IMS flange... but dont touch the bearing if it doesnt show sign of fatige... ? I dont know either. Dont get me wrong. I am not saying that one option is better than other. I am only saying that, internet has a lot of information and we tend to understimate the information coming from the manufacturer/developer and I think that, if you want to make the correct decission, it is important to balance all points of view. With all that been said, I am in the moment of changing belt and water pump... and honestly I dont know what to do. The workshop recommends to put the low temp... but I dont know if I am going to be more confident with the OEM thermostat or with one that I know was not the original design....

Quotes source post: 15553942

If Porsche was more vocal on communication and guidance, we wouldn�t have to make these decisions. The M96 engine just has too many design flaws. I mean, it took a class action lawsuit - that�s how you know someone screwed up. Porsche should design for 200,000 miles. Too many people are getting well under 100,000 miles. That�s not good. I have left my car alone in the thermostat realm. But if my thermostat failed, I�d put the low temp one in because under certain circumstances, on the track or under low air volume circumstances, it can run up to 236F (indicated), which is actually only 215F via ODBII measurements - both of which are not trustworthy, as verified by Raby and other actual measurements taken by the pros...Oil temps would be 15-20F higher than water temps, by the way.

Quotes source post: 15553706

The reason for slightly more power possible on just about any engine has to do with improving the air density intake charge associated with lower temps. Different engines have different values. But it�s pretty common across the board as a theory. Drag racers are doing 100-140F temps. Higher temps, however, improve efficiency by reducing drag from oil viscosity and from higher exhaust temps improving the air quality exiting the exhaust, driving down emissions. However, I�m skeptical of any significant or measurable power difference on this particular engine...

Quotes source post: 15551470

Unfortunately the piston pin cannot be raised in the m96/7 3.4 3.6 3.8 engines. They all have the same pin height but the 3.6 3.8 have a shorter rod( longer stroke crank). The pin is as high as it can go without getting into the oil ring groove. I know that other racing engines (SBC SBF) can move the pin up and even into (behind) the oil ring, but this cannot be done on the m96/7 engine because the pin has to be installed last ( through a hole in the block/case). Allthough not mentioned in the Hartech article, but has been discussed here, one of the big contributing factors of bore scoring is due to piston pin "offset" being favorable on bank 1, but unfavorable on bank 2 because both sides use identical pistons instead of side specific. The aftermarket pistons (JE ect) have no offset so are not favorable or unfavorable. Charles (L&N) had mentioned once that he had or did have some JE pistons that were side specific and favorable to both sides ( but that is not the ones they usually sell), and I'm sure JE would even built them for you if requested and coughed up a little more $$$.

Because I�m too lazy to dig it up: search the 996 section for my username and the word thermostat and you�ll see my thoughts and real world experience with a 160� thermostat. Long of the short, I�m more than pleased that I decided to install one 2.5 years ago.

Quotes source post: 15554532

Thanks Murph. Many years ago, we would swap out the higher temp thermostats in our MG's and Triumph for lower temp ones or simply run without any thermostat in the summer. I don't drive my 996 hard enough for a 160F T stat to matter. My bigger concern is making sure the oil is hot enough to boil off any moisture.

Quotes source post: 15555258

That makes sense, I wasn't even considering the wristpin installation when thinking about raising the pin. Would offsetting the pin cause the same issue with wristpin installation? I am not sure how much wiggle room is given for the access holes in the cylinders but it does make sense. Among the other issues mentioned in the article, it seems like the side loading of the thrust side of the piston is less than ideal. I will admit, I am kind of relieved the 3.4's don't seem to suffer from this affliction, though I am sure my motor has its own quirks to contend with.

Quotes source post: 15555466

I was initially concerned about that too, but I think short trips are the bigger issue. Cold engines will condensate water vapor a lot more than a warmer engine. With a 160F t-stat, you should still get a decent amount of water vapor released from the oil when it's up to temp with normal driving, especially in Florida. For example, check out the chart that shows water vapor pressure relative to temperature. As you can see, vapor is always being released, well before and well after the phase change point of 100C (212F). Remember, too, the crankcase is under a slight vacuum, which would help water vapor extraction as well.

Quotes source post: 15555603

Good stuff Murph. I googled around so take it for what it's worth but read the bottom of this page. It seems reasonable. http://www.vincihiperformance.com/LS...amshaft%20Life ! I'd like to see the makers of the 160F thermostat do some real testing with cylinder head temperature monitoring publish their data. Dave

Quotes source post: 15555512

The factory offset on the pin location is 0.5mm (.020thou), the aftermarket piston pins (JE) are not offset but there is no issues with installing the pins, there is enough wiggle room. The factory pins are offset 0.5mm to the intake (upper) side of the piston which is favorable to bank 1 but unfavorable to bank 2. Offsetting the piston pins gives more dwell time at TDC and softens the "snap" stress on the rods as they quickly change directions. The ideal pin offset would be 0.5mm toward the intake (upper) side of the piston for bank 1, and 0.5mm toward the exhaust (lower) side on bank 2, but will require two different pistons be manufactured to be side specific. A cost many "bean counters" deem not worthy, but as we have seen numerous scoring on the thrust side of bank 2, I think it is worthy on the m96/7 engines...

Quotes source post: 15556407

Hey, that's exactly what I found here too.

Quotes source post: 15555702

Good info. I agree with much of it. Engines are always a balancing act. I don�t think you can go too wrong either way, especially on the street if you chose either thermostat. I always am just careful that if the engine is hot while in traffic, and if traffic opens up, I don�t go to 100% throttle right away. I gradually get the airflow moving because it takes time to get to the engine to cool it down.

Quotes source post: 15557146

Reviving an old thread. I had differing opinions from two mechanics. One recommending 160 tstat and redline 5w40 and the other 180 tstat and M1 0w40 when I redid my water pump. my question is wouldn�t it be better to get oil and engine up to operating temp quicker? Most all engine operate in the low 200�s. I get the argument of having an open thermostat earlier, however, running an oil temp gauge I notice that even when water temp gauge is at operating temps oil is still in the 160�s for a while. When I had the lower temp tstat the car would run cooler longer but is this always a good thing? Isn�t oil designed to be operating at regular temp? Now that I have the 180, oil temps get to operating temp much quicker.

Yes, which is why the LN thermostat is the one to get. Starts opening at 160F, and opens fully at 180F. Best of both worlds. Just because water isn�t at 212F, doesn�t mean oil won�t shed moisture properly. And finally, in high ambient temps, you�ll probably run above 180 and we�ll into the 200�s unless you have a lot of airflow across the front radiators.