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Discussion Starter · #1 ·
The other day my 2009 g8 gt got a hot @ the drive true it didn’t reach the red but it was a quarter of the way there I turn ac on with heater full blast didn’t do much so I shut the car off for like 2-3 minutes fired it back up it was still hot but the temps came back down after 1 minute I assume the fans shut off or so idk why, it did it twice while I waited in the drive true went up turn car of and on and came back down has this ever happened to anyone it only happened to me while I was in the drive true it drove back home like it normally does the radiator and fans are stock and the fans are tuned to keep the car @ 160 degrees with the thermostat
I turned it on today I left it idling and it stay @160 for like 15 mins kinda weird I haven’t
 

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Welcome. Drive true?
 
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Methinks he meant drive thru🤔
And welcome!
 
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Discussion Starter · #4 ·
yeah pretty much it was @ a in n out I was there probably for 10-15 mins when I seen my temp gauge quarter away from red I cut the car off for abt a minute or so turned it on and like 10-20 seconds later the temp went down to normal within seconds any clue on what my issues could probably be it did it twice only it drove back home fine I started it yesterday I let it idle for 25 minutes and it was fine my question is why did it get hot in the first place
 

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It could be a multitude of things from a bad thermostat to a head gasket. Time to dive in deeper.
 

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Discussion Starter · #6 ·
the thermostat is abt a year old is it possible if it to go out so soon and the motor has 18k miles on rebuild there’s no milky stuff on oil cap and coolant was low but I’m guessing it’s low since it got past boiling point I am running distilled water instead of coolant
 

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... and coolant was low but I’m guessing it’s low since it got past boiling point I am running distilled water instead of coolant
Danger, danger Will Robinson. This does not compute.
 

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Check water pump bottom carefully, they are notorious for leaking while cooling down for weeks/months until it hits that low spot and creates overheating well known by those GM V8 truck owners !
 

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Discussion Starter · #10 ·
why are you not running coolant?

The system is pressurized, so the boiling point will be higher than normal, even with straight water.
That’s what the previous owner had in it also the thermostat is a 160 degrees and the fans are tuned to keep it @ 160 degrees theres never been pressure on the hoses since I got it also I check today left the car running for abt 35mins and only one fan was on is that normal ?
 

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If your car is indeed a V8 GT, you got a problem there. V8's either have "both" fans running in the low speed mode or the high speed mode depending on the engine coolant temp sensed or the existing high side psi of the refrigerant when the A/C is running. If your the T/S type, you can do some power checks and relay swapping to narrow down what may be wrong here.
 

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