Sudden overheat issue

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Sep 23, 2009 | 06:11 PM

SigmaX6

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Launching!

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From: Canada

Sudden overheat issue

Hey I know the basics on how to do the easy stuff. Flush, then swap out the thermostat. Where is the thermo located on these cars? Is there a better one to use(part #)?

Im looking for any other issues people might have encountered?

Issue: The car runs fine until I am stuck in traffic. At that time everything seems fine but after 10 to 15 mins the car begins to overheat really quickly.

The AC was not on during these times. I am not leaking as far as i can tell. I was about 1 litre down on coolant. Any mods i have had on my car for atleast 5 months.

07 Grand Prix GXP
Mods:
DIY Intake
Flipped motor Mount
Shift Kit
Finned trans pan
Trans Cooler (tru cool)
Trifecta Tune
Vector motorsports iat

Sep 23, 2009 | 06:47 PM

06 SS

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From: LITH, IL.

you wanna know about overheating? ask the man who has owned a V12 Jaguar. We can identify overheating causes in our sleep.

From your symptoms, your t-stat is fine. Also, water pump is likely fine as well. If the car cools down once you are moving, then it is almost for sure your electric fan. Either a sensor, relay, or the fan motor itself. Easy enough to check, See if the fan is running when it starts to heat up. A missing fan shroud or lower air dam can contribute to problems as well.

Sep 23, 2009 | 08:25 PM

SigmaX6

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Launching!

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From: Canada

The fans are running as to what degree i have no clue. They even run for awhile after the car overheats and then i shut it down. Misssing shrowed or air dam? i can see a air dam from the bottom of the car but i have no clue what the fan shroud looks like.

Thnks for your replies.

Sep 23, 2009 | 08:38 PM

smug_GXP

Staging Lane

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Is your temp gauge getting into the red or just up there?

Sep 23, 2009 | 08:58 PM

SigmaX6

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Launching!

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From: Canada

it'll get up to the red then the LCD display says turning off AC which isn't on as far as i know. and then it says turn off car immediately. Ive been to scared to let it hop up into the red honestly..Ive blown a couple head gaskets in my day from overheating.

Sep 24, 2009 | 02:20 AM

06 SS

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From: LITH, IL.

Ok, fan runs, one less thing to troubleshoot. (the fan shroud is the plasticky bit attached to the radiator that the fan nestles down in) If it still only happens when you are stuck in traffic and not moving, then your cooling system is still mostly working (i.e. water pump is spinning and t-stat opening up). First look up whatever procedure these particular engines have to bleed air out of the system and do it. Next step is to pressure test the system for a leak. If you get air in the system, it will migrate to the top and can cause steam pockets to form, it can also cause the water pump to cavitate (short term poor circulation, long term damaging the water pump). These can drastically raise your temps in certain spots and cause the overheating. If you locate a leak, repair/replace whatever is leaking, bleed the system and motor on down the road. If there is no leak to be found (and pay particular attention to the radiator fins and heater core), then I would look at (in order) a slipping belt, crappy mix of coolant (too much water vs anti-freeze), water pump, t-stat.

Sep 24, 2009 | 07:57 AM

SigmaX6

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Launching!

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From: Canada

My uncle has the equipment for doing a pressure and flush test. So im picking up a new stat and doing some work on it today. Ill chime back in if i didnt fix it. Gotta start somewhere.