Cooling fan mod or Lower T stat which one

After driving around in 90* heat and a lot of stop and go,.. I noticed the temp gage was a bit higher than I've seen in the past also the oil pressure was a bit lower too. I was right at the 3000 mile mark and is now due for an oil change however, I want to run cooler to protect the motor. So my question is.... Which is the more desirable method to run cooler when ambient temps are high. The FAN MOD or the LOWER T STAT mod or both? Thanks for the info I've done a search but could not find a definitive answer.

Fan Mod. Although I have both.

by fan mod I'm guessing its the keeping the high on by jumping the relay? Is that what we're talking about here?

Fan mod. Although i have both too. haha. My fan does not off at all. I use my aircon as the switch. When the aircon is off, low speed fan stays on. When the aircon is on, high speed fan comes on.

I have the ln 160 degree stat (no fan mod) and that does the trick for me. In 100 degree heat, the needle is never past the left side of the "0"

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I'm stock and also never past the "0" in regular street driving. If I change the water pump, then I would put in the 160 stat.

I love my fan mod.... stealthy switches,

IMO fan mod does more for less

T-stat is the way to go. It will actually make the engine run a little cooler. The fan mod is fun, but the fans should turn on when needed without the mod. One thing that owners should be aware of is that the temp sensor for the cooling system measures the temp after the coolant has been circulated through the radiators (therefore cooled to about the lowest temp it will get to) and returned to the water pump, but before it is circulated through the engine! This is also where the T-stat is located. What this means is that both the T-stat and the sensor are measuring the coolant temp at the point in the system where it is at the lowest temp. So when the temp gauge shows 180 degree that is after the coolant has been cooled down, the coolant exiting the engine flowing toward the radiators may (actually will be when the engine is warmed up) significantly hotter. So when the gauge says 180 degrees the temp of the engine is actually hotter than that.

I agree with your statement about the measuring point Doug....No question about it! but I personally think airflow is better than a lower opening point of the t-stat that in the end (rather 160 or 180) is wide open....either way, the thing is wide open and if temps are rising you need 1 of 2 things...more volume of water or more cooling of the water (via more surface area or more airflow) so without major mods (adding 3rd rad) or other the easiest way to get the heat out is thru airflow... this is an old debate, I doubt either one of us will convince the other which is "better" but that's my position and I am stickin with it (for now)

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Do you know if the temp sensor you are referring to is the temp sensor indicated for durametric readings or the climate control ecu reading? Those two readings are different. We are obviously splitting hairs now. Personally, I would prefer the engine to run hotter than cooler in the dash gauge for fear of excess wear and tear on a cold engine. What is the optimum operating temperature range for our engines? Which mod, fan mod or the T-stat, keeps the engine temp within that optimum operating temp better? I vote for the fan mod because it allows me to keep the coolant temperature consistent with highway driving temperature readings while on local "stop and go" conditions.

Just drive the car faster and it will get more airflow into the radiators. Oh, and keep your radiators clean. :-)

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The third rad is useless in stop and go traffic with no airflow to aid cooling.

I thought that if the AC is running or the coolant temp reaches a certain level the fans are running at high speed anyway. So once the engine is up to temp (the stock T-stat starts to open at 180 degrees and is fully open at 220 degree I think) then if the coolant starts to get "too hot" the fans should already be running. Won't a fan switch just allow you to turn on the fans even before the systems turn them on automatically? I know I bought all the relays, etc. to make the fan mod using a tip switch and have just never gotten around to installing everything, but I was just doing it for kicks. The low temp T-stat will start the flow of coolant sooner and allow full flow sooner which may have the engine run a little cooler except on really hot days when the controlling factor is going to be the size of the radiators. If I am correct about the fans running on high automatically then in hot temps neither the fan mod or the low temp T-stat is really going to do much, only more radiator capacity (i.e a third radiator) is really going to keep the temps down. IMHO

I don't understand why your temperature raise like that. I have been driving in 100F dry Texas and now in 95F humid florida and my water temp is always the same, not going up a hair. Of course with those temperature I always run with the AC on, so my fan are running in full blown. I think you might want to remove your bumper and clean your radiator. Phil

For lowering the temperature in stop and go traffic the fan mod is probably the most helpful. For minimizing hot spots in the engine and getting fluid flowing through the system earlier, the low temperature thermostat is more helpful. I've got the third radiator and lower temp thermostat and when cruising on the highway or at the track my temps are pretty low. When I'm in stop and go traffic things still get plenty hot. That's where fans help. -Shawn

If you haven't cleaned out the space between the rads and the condensers do that first! You would be shocked by the crap that will find its way between and slow down air flow.

My temp was doing this too in traffic and in hot weather, and I ended up having both of my fans and relays replaced. Since the replacement, my temperature stays right between the 8 and the 0, no matter what the conditions. I think I may have had one fan out for some time and it was barely holding on, and then the other went out which is when I really noticed the problem.

LOL. Another "oil" thread I can see it already. The fans are going to come on whether you want them to or not. The question is, are you going to be a worrywort and turn them on before they are going to anyways? And why do you think Porsche picked the temps to turn the fans on automatically anyways (stage 1 206F and stage 2 215F)? Why wouldn't have they picked 180 and 190? Probably SMOG. But do you think they would have picked 205 and 215 if they thought it was dangerous for the engine? I've driven through 115+ degree temps before uphill at 100mph and the stock cooling system adequately prevented the temp from going past the 0 in 180. Obviously I'm on the other side of the fence. I say don't mess with it, if the car runs 10-20 F degrees hotter sure I might be loosing 5 HP but at least I'm doing something for the environment. The best thing you can do, IMHO is add a third radiator to the setup. The only fan mod I might consider is the engine compartment fan hack to help in stop and go or idling on a hot day. I agree with Doug - Even with a thermostat that opens sooner or fans that click on sooner (or all the time) the car can still get hot, depending on how it is driven or the conditions. I wonder if any of the people who have done the fan mods have had more fan related problems sooner than those who have just left it stock.

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Totally agree! The wear and tear with the low temp stat is a non issue. The car warms up just like it did with the original stat but starts the flow of coolant sooner. The theory could be that opening the stat ealier reduces the "shock" to the engine (high temp engine, dramatically cooler coolant) associated with the OE stat. I've seen no impact on fuel economy or performance.

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Porsche still thinks their IMS bearing is adequately designed. This is their first gen water cooled flat 6 remember... Good thread https://rennlist.com/forums/996-foru...erheating.html Don't know if it is correct but "190F - 200F" = "87C - 93C" https://rennlist.com/forums/4292128-post17.html

I believe everything Dharn55 wrote in his last post is true, also according to Autofarm in the UK since coolant enters the case on 1 side & flows to the opposite side all the while being heated by each cylinder, the low temp thermostat's earlier opening helps to minimize excessive heat @ the far side cylinders for those of you who hit the high rpm's before full warmup.

Wow thanks for the advice are the fan temps controled by the computer ie: on at X temp and off at XX. If so can they be adjusted with a Teck 2 or HP tuner type of program. Its an 04 and has 29K miles on her. My rads are clean fans both work but my temps were above the 0 on the 180 mark. What I noticed mostly was the feel of the car, slight drop of oil pressure power seemed slightly down, not as responsive. Like it was melting a bit. Heat soak if you will. Maybe I just need to get use to how it feels. My vett performs the great even on 100+ degree days although she does feel like its melting too.