180 degree therm

I heard that if I go ahead and replace the stock 195 degree thermostat on my 03 GP GT with a 180 degree one, then I can expect less heat from my heater in the winter. Is this true?

It will make a little difference the most complaints come from drilled 160 degree stats but they are pretty easy to change so you could just put your 195 back in for the winter.

Is that assembly right below the throttle body intake?

I see that it is. So after I bleed out the air with the new 'stat in there, can I expect the radiator to fill back up with coolant from the reservoir? Or do I have to actually go ahead and manually add to the radiator?

You should leave the stock stat in it as it helps with the emissions of the vehicle. The hotter the better for emissions, provided the radiator fan is operating normally. If you decide to replace it, yes you have to fill the radiator first and make sure you have no air bubbles/lock in the system.

Are there any benefits when using a lower temp. stat? I know when i had my 94 S10 SS, i used a 165* hypertech stat and it would over heat alot especially on hot days.

I am constantly losing performance on my car due to heat. It has to cool down to have the acceleration I desire. I don't see any other way to do this...? I just get sick of waiting for my 'stat to open, so I can start going again. I mean; why are these performance 'stats marketed if they are incredibly bad? And why are all those GP's that do 14sec quarters using 180 or 160 degree ones?

#1. I'm doing 14sec 1/4s with the stock 195* thermo.

#2. If you put in a lower thermo, you coolant is just staying hot and circulating through the engine getting hotter and hotter. A lower thermo will only really help when you're on the highway and the air can pass through the radiatior. With out air passing through, the coolant can't cool down, which then leads the fluctuations in coolant temps.

#3. You need to put in a manual fan switch so you can control when your fans turn on. Without that, your fans will only turn on when your PCM tells them to. (I.E. 215* for low speed fan, 225* for high speeds). If you pick up a DHP PCM, it'll leave your fans on for 2 minutes after the car shuts down.


If you have a 97+ Grand Prix (not sure what other years this could work for), you can pick up Casper's fan switch and control your temps. This is found: Here (http://www.clubgpstore.com/itemview.asp?itemid=35) . Pretty much all plug/play, just run the switch into your dash to have control....

So is there any benefit at all from using a 180? Why do so many GP drivers put one in?

There's a big benefit if you're driving on the highway, or you can turn your fans on at any time (or a lower temp). A 180* by itself will just make the coolant just as warm as a 195* when stopped, but it'll get much cooler on highway driving.

My recommendation, if you're going to do a 160*-180* thermo, do a fan switch at the same time, cause that's the only way you will really benefit from it.


Most GP owners do it at the same time that they do a fan-control mod, just like I'll be throwing in that Casper's swtich when I get my drilled 180* thermo...

Doesn't the GP DHP PCM do temp-controlled fan turn-ons for you?

What about the -40 degrees additive to the coolant?

Originally posted by ipec
Doesn't the GP DHP PCM do temp-controlled fan turn-ons for you?


Yes, I *believe* it turns it on at either 180 or 185*. However, I won't be able to afford this anytime soon, so I'll just go with the fan switch...

Here's what 3800Performance says about the SLP 'stat:

If you're looking for a quick and easy way to gain horsepower from your 3800-powered car, this is it. SLP Performace Parts offers two performance thermostats to lower engine operating temperatures, while increasing thermal efficiency and your engine's performance in the process. Lowering your engine's operating temperature will not only increase performance, it will add reliability and longer engine life, by decreasing the stress caused by heat fatigue. This thermostat will make a performance difference on even a stock engine. SLP's thermostats are a bolt-on piece that is of OEM quality.

So this is a false claim? It really doesn't do anything for your vehicle?

If it is true why would someone pay 3 times as much for a SLP stat instead of going to Autozone for the same temp. stat for a lot cheaper. On my S10 the Hypertech stat was $25 for a 165*, Autozone had a 165* for $6. Whats the true difference?....namebrand? probably.

Well, the "performance" ones have holes drilled in them.

Technically, it's not a false claim. They say that it helps your stock engine run cooler, which is true. It's true at highway speeds. At stop/go traffic, the coolant fluctuates because it's being cooled, then sitting there, then cooled, and the cycle repeats. With highway, it's much coler because of the consant flow of air at the higher speeds, so it does cool it to 160-180*.


Since one itype of driving is right, and the other just does what the stock one does, they're right. IT 'does' improve performance and reduce engine temps.




As far as the difference with name brand t-stats, the only reason i could see hypertech as a more pricey that a generic Pep Boys one is that it could be thicker, more durable, or something like that. :dunno:

I heard that if I go ahead and replace the stock 195 degree thermostat on my 03 GP GT with a 180 degree one, then I can expect less heat from my heater in the winter. Is this true?

ADD SOME WATER WETTER.