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Pintobean11
05-29-2012, 02:39 PM
Being down here in Florida my car seems to run hot. I know the stock thermostats are around 195 but I'd like to switch out to a 180 possibly a 160. Do you guys have one installed or do you know where to locate one?

mfuller
05-29-2012, 03:01 PM
You can order a 180 degree thermostat here:
http://www.pfyc.com/pc/GA3002/GAUNDER/Hypertech+PowerStat+Thermostats.html

Don't go to 160; too cold for a daily driver.
Ideally, you'll want to find someone with a PCM tuner to adjust your fan turn-on/off points.

Pintobean11
05-29-2012, 03:05 PM
Good stuff, thanks for the link.

Sucks that shipping is $1 less than the actual product.

AaronGTR
05-29-2012, 07:50 PM
Actually I'd stick with the stock T-stat. These engines are made to run hot. Anything from 195 to 230 is normal. The fans aren't even programmed to kick on until then. If you want to do anything, you can drill a few holes in the stock T-stat. That will let a little coolant circulate even when it's closed to gradually warm up the radiator, and will slightly increase the flow when it's open.

Basically it's just a waste of money, even with tuning. The rest of the cooling system has to be able to shed the heat, otherwise it won't do anything. If it's hot outside, your T-stat will open early, but your car will still run hot because the radiator capacity is too small to get rid of the heat. If it's cold enough outside, then your engine will run cooler... but you won't make any more power and your gas mileage will suck because the PCM is programmed to run richer at cold coolant temps. Save your money for real mods.

UndeadGods
05-30-2012, 07:24 PM
You can rewire the fans so that you can manually turn them on by hitting a switch when the car is running hot. Thats a lot of work tho.
As for location of one, its right UNDER your throttle body, left of your air box/CAI if you have one.
I was thinking of dropping a 180 cuz the 195 makes me think that my car will overheat =/
But it will rob your engine of your performance as Aaron stated, as for gas mileage sucking comment, I dont think that it can get any worse than it already is, hehehe

destroyer179
05-30-2012, 10:32 PM
Also, the thermostat in the GA is in the absolute worst possible spot. It's under the intake and there is about a mm of space to get your wrench in there lol

Pintobean11
05-31-2012, 10:50 AM
Why would the performance of the car drop by putting in a lower thermostat. It's science that cars running significantly better with a lower temp.

AaronGTR
05-31-2012, 05:55 PM
Why would the performance of the car drop by putting in a lower thermostat. It's science that cars running significantly better with a lower temp.


No, that's a common misconception of people who don't understand how modern engines run. lol The performance probably won't drop, but you won't gain any power from it either. And like I said it probably won't make any difference in what temp your car actually runs at most of the time. Just because the thermostat opens earlier doesn't mean your car will actually run colder.

rocketfast123
06-01-2012, 08:09 AM
If your car is running hot you got other problems. Last time coolant was changed? Is your a/c condenser full of love bugs?

Pintobean11
06-01-2012, 10:20 AM
My Z28 sure ran 5x better when I put the 160 thermostat in it. Maybe Pontiacs different.;psycho

The car is running right around 205 and we haven't even hit August yet. I'll be changing the fluid out when I install the new thermostat and probably going with more water than antifreeze as well to cool it even more.

locoman99
06-01-2012, 10:53 AM
My Z28 sure ran 5x better when I put the 160 thermostat in it. Maybe Pontiacs different.;psycho

The car is running right around 205 and we haven't even hit August yet. I'll be changing the fluid out when I install the new thermostat and probably going with more water than antifreeze as well to cool it even more.

It would be a long explanation..but lets just say a 160 thermostat will hurt more than help.

If u want your car to run cooler the easiest and best way is to buy a kit that lets u turn on your fans manually, they are available from a couple sources.

And save your self the headache and just pull the uim when u change the thermostat

AaronGTR
06-01-2012, 02:41 PM
My Z28 sure ran 5x better when I put the 160 thermostat in it. Maybe Pontiacs different.;psycho

The car is running right around 205 and we haven't even hit August yet. I'll be changing the fluid out when I install the new thermostat and probably going with more water than antifreeze as well to cool it even more.


Like I said, these cars are designed to run hot! The computer isn't even programmed to turn the fans on until 230. I live in FL too, and I have a custom oversize radiator, a drilled 195 T-stat, and my PCM is programmed to turn the low speed fans on at 200 and high speed at 225. Guess what.... I still hit 205-210 regularly! It's not a problem. Your car is fine, and I highly doubt anything you do to it will make it run any cooler, or that it would help anything anyway.

mfuller
06-01-2012, 03:34 PM
If you do a lot of low-speed or city driving or you are stopped a lot, there's little you can do to keep the coolant needle from rising. Without fresh air costantly flowing through the radiator, the temperature will go up - simple thermodynamics.
I have a 180 degree thermostat and a 2" thick aluminum radiator. When cruising, I'll stay right around 179-180 degrees. But if I stop for an extended length of time, all bets are off, especially if the ambient temperature is over 90 degrees.
I really wouldn't worry about it too much.
When was the last time you flushed your coolant?

over's ga
08-04-2012, 05:15 PM
Like I said, these cars are designed to run hot! The computer isn't even programmed to turn the fans on until 230. I live in FL too, and I have a custom oversize radiator, a drilled 195 T-stat, and my PCM is programmed to turn the low speed fans on at 200 and high speed at 225. Guess what.... I still hit 205-210 regularly! It's not a problem. Your car is fine, and I highly doubt anything you do to it will make it run any cooler, or that it would help anything anyway.

Aaron, on an '04 GA SE. 3.4, is the fan on temp the same as the earlier cars? I just did 3500 swap on unfamiliar car, and I'm paranoid its going to overheat and do damage to my low mi. 06 malibu 3.5 do you know best place to take accurate temp reading with laser temp gun?
**and how hot I should let it go before damage and melting overheat warranty buttons, just in case I have fan circuit problems. Thanks in advance..

see end of this thread;
http://www.grandamgt.com/forum/showthread.php?t=87701
subject starting at post #46

2000 GT Coupe
08-04-2012, 05:25 PM
I have lived in florida for the last 2 years and since I moved down here I pulled the t-stat out completely my pcm is set for fan on at 180 and my temps only go over 202 if there is a problem.

summer and winter the car runs at 200 just about on the dot.
when the temps are 50 outside (rarely) it takes about 1.75 miles to heat up to 200.

Just to clarify though this is all in town driving. Highway would be slightly different. I have driven down to west palm in feb with it and the temps were between 180 and 192


Edit I may need to reexamine this after flushing out the radiator by this time it could very well just be partly clogged.

ponson00
08-04-2012, 06:17 PM
I remember reading somewhere that one of the reasons for these cars being set to run hotter was to prevent build up in the engine....don't know if that is true or not. For the people who are drilling holes in their thermostats will that cause any problems that might harm the engine or radiator?

over's ga
08-04-2012, 06:35 PM
I remember reading somewhere that one of the reasons for these cars being set to run hotter was to prevent build up in the engine....don't know if that is true or not. For the people who are drilling holes in their thermostats will that cause any problems that might harm the engine or radiator?

drilling holes in t state is old school trick, not sure of true pros or cons, but should be ok and better then removing completely (much debate on complete removal)

high temps (I think for most part) are engineered into modern cars for emissions & fuel efficiency, problem is if your engine or cooling system is marginal your allready at edge of overheating

AaronGTR
08-04-2012, 07:02 PM
Aaron, on an '04 GA SE. 3.4, is the fan on temp the same as the earlier cars? I just did 3500 swap on unfamiliar car, and I'm paranoid its going to overheat and do damage to my low mi. 06 malibu 3.5 do you know best place to take accurate temp reading with laser temp gun?
**and how hot I should let it go before damage and melting overheat warranty buttons, just in case I have fan circuit problems. Thanks in advance..

see end of this thread;
http://www.grandamgt.com/forum/showthread.php?t=87701
subject starting at post #46

Fans speeds should be the same between years as far as programming in the PCM goes. I'd have to look at the program in my tuner to be sure of course, but I've never heard of any different temps in the program, and all the years I've looked at so far have been the same.

I wouldn't know a good place to read with a laser temp gun. Never needed it. The stock gauge gives you a pretty good idea, and using a scanner will give a more accurate number. I suppose if your gauge/coolant sensor was malfunctioning you might need to do that to check the actual temp. The radiator would probably be closest to actual coolant temp in that case. Anywhere on the engine is going to have heat soak.

I don't know what temp those warranty discs melt at, but anything up to around 230 is fine. The red zone on the gauge goes from 230-260, and the high speed fans kick on at 230... so if it goes over 230 without the fans kicking up a notch there is a problem, and if it gets to 260 you might warp something.


I remember reading somewhere that one of the reasons for these cars being set to run hotter was to prevent build up in the engine....don't know if that is true or not. For the people who are drilling holes in their thermostats will that cause any problems that might harm the engine or radiator?

drilling holes in t state is old school trick, not sure of true pros or cons, but should be ok and better then removing completely (much debate on complete removal)

high temps (I think for most part) are engineered into modern cars for emissions & fuel efficiency, problem is if your engine or cooling system is marginal your allready at edge of overheating


Drilling holes in the T-stat won't hurt anything, as long as you aren't drilling them so big that they damage anything and affect the operation of the T-stat. I don't really recommend removing it completely, even if you live somewhere warm. It still warms up faster with it in, and you aren't gaining much with it out. You will still be limited in cooling by the size of your radiator. Also in some cars pushing the coolant through the radiator too fast actually hurts cooling by not giving the coolant enough time in the radiator to shed heat. Depends on the car though.

The biggest reason to drill a T-stat is to let the coolant in the radiator warm up gradually before the T-stat opens. This is especially more important on cars driven in cold climates that have iron cylinder heads. Guys with older grand prix GTP's in the northern states were finding that when it was really cold out the coolant in the radiator would be very cold, and when the T-stat opened they would get a sudden rush of cold coolant hitting the hot cylinder heads and it was causing them to crack. A few 1/8" to 3/16" holes will let some coolant circulate before the T-stat opens and slow bring the radiator up to temp. It also will increase the coolant flow to the radiator a tiny bit, but nothing too significant. And on a car with aluminum heads like ours, or if you live in a warm area, it's not as important... but it's still not a bad idea. Especially if you live up north.

over's ga
08-05-2012, 12:40 PM
Fans speeds should be the same between years as far as programming in the PCM goes. I'd have to look at the program in my tuner to be sure of course, but I've never heard of any different temps in the program, and all the years I've looked at so far have been the same.

I wouldn't know a good place to read with a laser temp gun. Never needed it. The stock gauge gives you a pretty good idea, and using a scanner will give a more accurate number. I suppose if your gauge/coolant sensor was malfunctioning you might need to do that to check the actual temp. The radiator would probably be closest to actual coolant temp in that case. Anywhere on the engine is going to have heat soak.

I don't know what temp those warranty discs melt at, but anything up to around 230 is fine. The red zone on the gauge goes from 230-260, and the high speed fans kick on at 230... so if it goes over 230 without the fans kicking up a notch there is a problem, and if it gets to 260 you might warp something.

Thanks, I'll disconnect fan jumper and let the computer do its thing, later today will be 110 lets see how long it takes to kick on. Temp gun will still be ready towards the end to get relative idea of temp.

Is high speed fan on passenger side?

AaronGTR
08-05-2012, 07:27 PM
Nope, it's both fans. IE it doesn't turn on one then the other. It turns on both fans on low speed, then both fans kick to a higher speed when it reaches the preset temp for high speed fans.

spatton1
08-06-2012, 11:06 AM
Not to hijack a thread but on the subject of temps. Is the tranny designed to withstand the temp of the motor "running 210 to 230" the reason being is that my tranny is shot and I have to do alot of in town driving.

over's ga
08-06-2012, 11:31 AM
yesterday got fans to kick on, yep both fans went on, took less than 20 minutes when idled up to about 1500. it got HOTTER QUICK, I screwed up. :banghead Day before rad hoses were on w/o clamps, system air was bled & full of water, this time I filled it up but forgot to bleed air (overnight it trickled water out of loose hoses!) it shot up close to red on gage until I figured out what all the gurgling and boiling water sound was (air bubble)
*Don't forget to bleed system!*

On trans temp, having the trans fluid next to engine coolent that's 200+ degrees (in Radiator) most times can't be best for long life. not a lot of room for separate cooler/fan but having fans on earlier may help, also the simplest way is to flush and change trans fluid on regular basis, its the life blood and it does wear faster in higher temps.

spatton1
08-06-2012, 02:26 PM
yeah did that but its too late lol

AaronGTR
08-06-2012, 10:13 PM
Yes, the trans is fine at that level. The fluid is formulated for that, and the trans fluid cooling coils are inside the radiator end tank for a reason. It's on the return side of the radiator, so the trans fluid gets coolant that has gone through the radiator and cooled off some. Remember, your coolant temp sensor is in the LIM at the T-stat housing where it is at full temp after it has come out of the engine block and cylinder heads. It is a little cooler after going through the radiator, but keeping the trans cooler in the radiator helps get the trans fluid up to temp quicker so it lubricates better. The trans takes a while to get up to temp otherwise, and the fluid works best in a certain temp range (normally 180-210). The manufacturer designs the system to get the fluid up to temp quicker then hold it in the optimum range during normal driving.