On my Gst I had never had an overheating issue. But I just noticed last week and on the way to MOD, my temp needle starts creeping up above normal temp ( the halfway mark) slowly and when it does, I turn my a/c on (in order to kick the a/c fan on) it drops right back to normal temp (halfway mark). This only happens on the freeway ONLY.. I put a new thermostat, radiator flushed my MISHIMOTO before heading to MOD and still, my needle started creeping up so I turnt my a/c on to drop it back down. In the city, stop and going in this heat 98+ degree weather, i stays at normal temp. shouldnt it be the other way around? overheat in city driving ( stop, goin,) and on freeway it should run cooler since im going 70mph? Also last night, i ran my car pretty hard while i was doing some safc tunning and to see if the temperature starts creeping up, but it runs at normal temp even if im running her hard. any input would be greatly appreciated. And sorry for long post, but i HATE overheating problems
Do our fans have 2 different speeds? Is my a/c fan suppose to kick on after a certain temp, even tho my a/c is OFF? And yes, my fan turns on.. Any of you guys have/had this problem?..

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THE FANS ARE 3 speed (counting off) .Also, I had the same issue on my way to MOD and back home also. Only when going uphill or boosting hard /high reving the temp would creep up but then it would drop to normal temp . I only had 1 slim fan . Got home and installed a 12" pusher and havent overheated , atleast yet.. And i have a 170* thermostat , fresh coolant, aluminum radiator, and the turbo set up is on my profile..

I think you guys should do some ducting work to improve airflow.

gho5tone said:

I think you guys should do some ducting work to improve airflow.

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Yea, thats what im planning on doing, and getting the RoadRaceEngineering Hood Vent to cool this thing down.

If fine when not moving, it means your fans are doing their job properly.

If not fine while moving, it means your radiator isn't getting enough air through it because it is being blocked by your AC condenser and FMIC.

Try running a little bit higher of a water:coolant ratio. And maybe some coolant additives like Neo Synthetic's "Keep Cool". And be sure to burp the system as much as possible before letting it finish the rest of it for you.

Atleast in my case, when im going up hill it"ll start climbing up, then it would drop when im on a constent speed "getting air" and on traffic it would climb up then continue driving and it would drop to normal. Now that i installed the pusher 2nd fan , the temp hasnt gone up, Atleast yet.

That's strange that you have both as a problem. But at least the push fan is helping.

Question for you: Do you have any space between the bumper and the FMIC where the air can escape? That would cause the freeway issues too.

BoostFrenzy said:

That's strange that you have both as a problem. But at least the push fan is helping.

Question for you: Do you have any space between the bumper and the FMIC where the air can escape? That would cause the freeway issues too.

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Nope not allot, still neet to trim the center of the bumper cause of the front mount.

BoostFrenzy said:

That's strange that you have both as a problem. But at least the push fan is helping.

Question for you: Do you have any space between the bumper and the FMIC where the air can escape? That would cause the freeway issues too.

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Ya well I got space between my fmic and a/c condenser. I was thinking of putting a slim fan between there but im not sure if that will even help out cus the condenser is in the way of pushing air to the radiator.

For me in uphill, it doesnt Start to creep up. It's fine temperature there. I only have a problem when im in freeway going 65+mph

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805DSM said:

THE FANS ARE 3 speed (counting off) .Also, I had the same issue on my way to MOD and back home also. Only when going uphill or boosting hard /high reving the temp would creep up but then it would drop to normal temp . I only had 1 slim fan . Got home and installed a 12" pusher and havent overheated , atleast yet.. And i have a 170* thermostat , fresh coolant, aluminum radiator, and the turbo set up is on my profile..

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So my regular fan(passenger side ) has more than one speed? It kicks on and after it gets higher temp it should kick into a faster/stronger speed? What about the a/c fan.. is that suppose to come on after a certain temperature even though if I have my a/c OFF?

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deviousgst said:

Ya well I got space between my fmic and a/c condenser. I was thinking of putting a slim fan between there but im not sure if that will even help out cus the condenser is in the way of pushing air to the radiator.

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Thats what i did , and so far the temp hasnt creeped up.
I hooked it up to the a/c harness and it turns on once i have the a/c button on.

deviousgst said:

So my regular fan(passenger side ) has more than one speed? It kicks on and after it gets higher temp it should kick into a faster/stronger speed? What about the a/c fan.. is that suppose to come on after a certain temperature even though if I have my a/c OFF? .

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They both have a "High & Low " speed . Depending on the temperature the high or low speed kick in.

805DSM said:

Thats what i did , and so far the temp hasnt creeped up.
I hooked it up to the a/c harness and it turns on once i have the a/c button on.
well i got my a/c hooked up but my a/c isnt that cold becaus i need freon.
so when it does start creeping up i turn on my a/c and it comes out hot so thats why i wanna make sure my radiator fan is working properly because it sucks when hot air is hitting your face





They both have a "High & Low " speed . Depending on the temperature the high or low speed kick in.

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hmm.. how would i know if it kicks into high speed?
i checked my fan relays by using a 9v battery

I wonder if your thermostat isn't working properly. Perhaps it's not opening enough and so not allowing enough coolant flow and you run into the threshold of the system only while driving.

A local dsmer had this issue as well. It turned out to be a small pin hole in the coolant line that goes threw the OFH. He replaced every hose then found out it was the only one he forgot about.

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TSiAWD666 said:

I wonder if your thermostat isn't working properly. Perhaps it's not opening enough and so not allowing enough coolant flow and you run into the threshold of the system only while driving.

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im prettty sure it is, well not positive, but its a new thermostat

Doubleot said:

A local dsmer had this issue as well. It turned out to be a small pin hole in the coolant line that goes threw the OFH. He replaced every hose then found out it was the only one he forgot about.
i dont see any leaks though. i checked and doubled checked.
im not even loosing water or nothing. this is weird

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this is a really weird issue because i still have a/c and my car doesn't over heat at hwy speeds. are you sure you don't have any coolant leaks? is your timing set correctly? how many times have you burped the system? if all the listed above is fine i would say your radiator is partially clogged or you simply aren't flowing enough air through the radiator itself which means you need to start making some ducting between the radiator and a/c condenser....


edit: you could also try running a lower degree thermostat. i think the parts store makes a 160 for our cars.

I added a front carbon fiber vent to get more air to the radiator (fmic blocks the bottom opening) got a lower temp 180 thermostat and I placed duct tape to seal the side gap between my mishimoto slim fans and the oem radiator and (*knock* on wood) the temp gauge hasn't gone past the middle part of the gauge.

Change the thermostat try to get am OEM one
I have the same issue. My thermostat got stuck open and it was one of them autozone ones that have a fail safe when it gets super hot and stays open

When a thermostat stays open the coolant will not cool Down coolant needs to stay in the radiation to cool down when the thermostat reached the temp range it opens releasing all that cool coolant
A thermostat that is used in automobiles uses an internal combustion engine to regulate the flow of the coolant. When the thermostat is open, the coolant passes through the cylinder head where it looses the heat the air that flows through it. A water pump that is driven from the engine will propel the coolant around the system. When the thermostat is closed the flow is then prevented and the engine is then allowed to heat up to its optimum temperature.

If you rule out cooling system problems and the overheating is still there; do a leakdown test on it. I had this ongoing problem since owning the white talon. Turned out to be a warped block. When the previous owner rebuilt the engine, he did not check the block. This surprised me, as usually overheating on the highway is indicative of a head gasket problem or warped head.

But before going there, make sure everything in your cooling system is working properly.

Had the same problem as well with one slim fan. Added a condencer fan from a Stratus and it worked great!

just reading over this I had two hoses burst (lower radiator and some small line our of the thermostate) I replaced them all. But for some reason when I drive for a long time my car hold temp, then if i turn it off after a long cruise, and turn it back on with in about 15 min (to run into mcdonalds or something ) and come back out and turn the car on my temp gauge goes up over half, but as soon as i put it in drive and it starts rolling it climbs down slowly then hold again. I just think my car is odd but wondering if this happenes to anyone else? Oh and fyi it did not do that before I replaced the hoses.

deviousgst said:

Ya well I got space between my fmic and a/c condenser. I was thinking of putting a slim fan between there but im not sure if that will even help out cus the condenser is in the way of pushing air to the radiator.

For me in uphill, it doesnt Start to creep up. It's fine temperature there. I only have a problem when im in freeway going 65+mph

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Who need's AC when you live in cali? If I lived in flordia I would have AC.

OP, are you sure your fan is comming on while driving? Maybe you water pump is on it's way out.

sorry everyone for a late update. but i dont overheat anymore on freeway..
i ended up installing a fan between my a/c condensor and FMIC..