# overheating



## xcmac26 (Dec 1, 2008)

Radiator boiled over twice today. just breaking 80 degrees here in houston. cranked up the heat to try and get it to cool off, no dice. anyone have a suggestion here? I'd rather not kill my motor.

also, any possibility i accidentally messed with the thermostat when i popped off my valve cover on the driver's side? :confused


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## Rukee (Feb 8, 2007)

did you remove the thermostat housing when removing the valve cover??
Could be a bad stat, water pump, collapsed hose, bad clutch fan, no shroud, restricted radiator, crud in the block....


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## jetstang (Nov 5, 2008)

No chance you messed with the stat pulling a valve cover. But now you need to. Summer is here, get a 165 degree thermostat and try that. heat won't work very good, but it's summer, and may be your problem if it didn't overheat before.


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## xcmac26 (Dec 1, 2008)

all i took off was the air filter and the valve cover. moved the plug wires out of the way. didn't touch the radiator (or didn't intend to) 

just had it out in the cool 70-something air. no overheating. apparently 80's the magic number. i'll give the new stat a whirl, probably flush the radiator and get some new fluid in there. thanks for the tip.


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## PBF Bioset (Apr 25, 2010)

Did you lost any refrigrant?
The cooling system stands under pressure to realize a superheating. If the system is leaky the waterpart of the refrigrant boils at nearly 100°Celsius...212° Kelvin...
I've had that too month ago. The engine heats up very fast as it was shown in my cluster (? instruments)...
In my case a small tube to the throttle body, which should heat it up on low temperatures was rough.


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## Rukee (Feb 8, 2007)

PBF Bioset said:


> Did you lost any refrigrant?
> The cooling system stands under pressure to realize a superheating. If the system is leaky the waterpart of the refrigrant boils at nearly 100°Celsius...212° Kelvin...
> I've had that too month ago. The engine heats up very fast as it was shown in my cluster (? instruments)...
> In my case a small tube to the throttle body, which should heat it up on low temperatures was rough.


Refrigerant is used for the Air Conditioning(A/C) unit to cool the inside of the car, not to cool the engine.
The engine uses coolant to dissipate heat, which if it's low could cause an overheating problem as well.


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## 68greengoat (Sep 15, 2005)

80 deg. should not make your radiator boil. Is it boiling, or, are you just losing fluid? Do you have an overflow tank? If not, did you fill the rad to the top and the system is just dumping out the extra fluid? The fluid level should be an 1 - 2" below the top without an overflow tank. What does the temp gauge say when it's overheating? If it really is overheating, I would start by replacing the stat first and see if that solves your problem... May not be opening all the way.....


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## GTO JUDGE (May 14, 2005)

NAPA carries a high flow 160* T-stat I just put one in. About 8-9 bucks.


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## PBF Bioset (Apr 25, 2010)

Rukee said:


> Refrigerant is used for the Air Conditioning(A/C) unit to cool the inside of the car, not to cool the engine.
> The engine uses coolant to dissipate heat, which if it's low could cause an overheating problem as well.


Oh. Ok thank you ^^
The dictionary doesn't differentiate this exactly. It's sometimes hard to find the right technical terms, because I translated it from spoken speech. That's why I'm glad of being corrected. 
I think this is called language barrier :cheers 

Thanks again


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## hookemdevils22 (Mar 27, 2010)

PBF Bioset said:


> Did you lost any refrigrant?
> The cooling system stands under pressure to realize a superheating. If the system is leaky the waterpart of the refrigrant boils at nearly 100°Celsius...212° Kelvin...
> I've had that too month ago. The engine heats up very fast as it was shown in my cluster (? instruments)...
> In my case a small tube to the throttle body, which should heat it up on low temperatures was rough.


I think you meant 212° Fahrenheit ... 212 K = -60°C = -78°F, and I'd hope it wouldn't boil over that low!


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## PBF Bioset (Apr 25, 2010)

hookemdevils22 said:


> I think you meant 212° Fahrenheit ... 212 K = -60°C = -78°F, and I'd hope it wouldn't boil over that low!


Oh man. Today is not my day ^^


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## xcmac26 (Dec 1, 2008)

The car's been running fine up until the temps got hot the other day. I will check the coolant levels when i get home. I don't have an overflow tank, so it's just spilling from the hose onto the ground. wouldn't surprise me if there were a leak somewhere in the system, although the radiator and hoses all seem to be relatively new. Thankfully haven't seen any cloudy oil.

maybe there should be an overflow tank so i don't kill all squirrels and rats running around houston...on second thought 

I'll also swing by O'reiley and see what they have for thermostats when i get out of work, it's summer, no sense in running the heat anyway.


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## 66tempestGT (Nov 28, 2009)

im sure you are just joking but the overflow tank is to catch coolant that expands at operating temp and wont fit in the system anymore then it siphons back in when everything cools back down later. did it seem to be actually boiling or just pushing some water out? is this the first summer you have been driving it?


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## Rukee (Feb 8, 2007)

If you top off the radiator when cold or hot and the put the cap on, it WILL spit some out the over flow tube when it gets hot. It should stop after a while. Then after it stops let the engine cool and pull the cap off, the level should be down by about 1". That is normal. Just leave it there and don't top it completly off from now on.


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## xcmac26 (Dec 1, 2008)

well the fluid was about halfway down in the radiator. topped it off to about 2-3 in. from full. boiled over after a short drive up the road. I'm going to give the thermostat a try in the morning.


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## Rukee (Feb 8, 2007)

After you change the stat, leave the cap off and let the engine run with the heater going on hot but no fan inside. Leave the cap off until you see the antifreeze flowing and the upper hose gets hot and verify that the thermostat is working. Once it's flowing, slam the cap back on and you should be good to go.


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## jetstang (Nov 5, 2008)

Before you install the thermostat, drill a 1/8" hole in it so it will fill the water jackets so you don't have to wait til the thermostat opens to make sure you have all the coolant in it. It may take a little longer to warm up, but it is worth it up front.


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## xcmac26 (Dec 1, 2008)

Crunch time, and i'm stuck. the forward bolt of the radiator housing won't come out. I've tried penetrating oil, dry ice, propane torch...nothing. I don't have impact tools so i can't do anything there. anyway, my question's this. The rear bolt is pretty standard, but the one i've got on the front had a castle nut on it (which i removed) and what looks to be a flare nut welded to threaded rod. is it supposed to be like that? I have to get this sucker either put together or changed out to the new stat by noon tomorrow so anything is helpful. thanks guys.:cheers


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## 68greengoat (Sep 15, 2005)

Should be just 2 standard bolts. Sounds like someone jury rigged it. Can you take a pic and post it up? Maybe soaking it in penetrating oil overnight will help loosen it....


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## jetstang (Nov 5, 2008)

Get a bigger wrench, snap it off and tap and tap new threads if it comes to that. I assume you are talking your thermostat housing. Dissimular? metal corrosion and no anti seaze will cause this. The bolt wont come out of the intake if it's that stuck. If it does, it's taking the threads with it, and you'll still have to heli coil it. I have sensors on old intakes that I know will never come out.


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## xcmac26 (Dec 1, 2008)

given I have work and I need to be on the road by noon...the car's at a mechanic :willy:

they can have the pleasure of breaking the bolt and drilling/tapping the intake.


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## xcmac26 (Dec 1, 2008)

jetstang said:


> Get a bigger wrench, snap it off and tap and tap new threads if it comes to that. I assume you are talking your thermostat housing. Dissimular? metal corrosion and no anti seaze will cause this. The bolt wont come out of the intake if it's that stuck. If it does, it's taking the threads with it, and you'll still have to heli coil it. I have sensors on old intakes that I know will never come out.



I put a cheater on the wrench and actually started flexing the jaws. i need better quality tools :shutme

need to go by some estate sales or something.


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## Rukee (Feb 8, 2007)

Get a bigger tourch too. :cheers

The blue tipped wrench!


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## y2kjammer (Dec 18, 2009)

Agree - Flame wrench. If it isn't 'cherry', it isn't hot.


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## xcmac26 (Dec 1, 2008)

well, to tie this one up...mechanic got it squared away in about 20 minutes with a torch and an impact wrench. my lack of space and proper tools here in tx is really starting to piss me off 

and oddly enough, that little propane torch got the bolt a nice rosy shade of red, but it very quickly cooled back down. in either case, that sucker was in there good. 

anyway, got the car back and hauled ass out I-10 doing about 80 the whole time, no overheating!!  i think the torrential rainstorms helped with that though. i got drenched from rain coming through between the top and the windshield, need some new weatherstripping up there :lol:

car made a hell of a splash at my friend's wedding too. lots of guys fawning over it and telling me stories about gto's they had or this and that car. grooms mother actually had the biggest reaction, apparently she and her sister dated a couple guys with a 68 and 69 gto and lemans. i didn't let her in the car :rofl:

followed the weekend up with a nice cruise back from shiner on TX hwy. 90. stopped at bob's taco station for snowballs, tamales and tacos (was on diner's drive in's and dives, feckin delicious!) all with the top down. great weekend overall and a nice little sunburn as evidence.


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## Eric Animal (Oct 28, 2007)

better take it easy on those Tamales...or you'll be adding a Legendary seat kit to the list of stuff you need!!arty:


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## jetstang (Nov 5, 2008)

Eric Animal said:


> better take it easy on those Tamales...or you'll be adding a Legendary seat kit to the list of stuff you need!!arty:


True, if he had a cloth interior it would just get obsorbed into the foam.
Congrats!!!
What was the cruising temp, and what did you get for MPG, or do you just fill it up and not worry about it.


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## mp4life23 (Apr 28, 2010)

what is normal operating temp for my setup im at 210-212 crusing and 215-220 at idle the funny thing is when i shut the car down the temp guage goes way up like 250 or so then when i start it back up it drops back down. I have a thermal temp gun where can i check the temp of the engine and get a acurate reading.


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## Rukee (Feb 8, 2007)

mp4life23 said:


> what is normal operating temp for my setup im at 210-212 crusing and 215-220 at idle the funny thing is when i shut the car down the temp guage goes way up like 250 or so then when i start it back up it drops back down. I have a thermal temp gun where can i check the temp of the engine and get a acurate reading.


Totally normal for the temp to go up after you shut it down.
You could do a 180 or even a 160* thermostat instead of a 190* and drop your temps a few degrees.


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## jetstang (Nov 5, 2008)

:agree No need for a 180 stat if you don't have a heater, which I don't think you have. If you can keep that car from overheating in traffic, you are doing good. As you overbore, the walls get thinner and can't disipate heat as well, so temps go up, add compression, and they go up more. Pontiacs run hot from what I've learned. So, biggest radiator that fits and extra electric fans to keep it cool. The best scenario is the temp guage bouncing off the thermostat temp.


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## xcmac26 (Dec 1, 2008)

jetstang said:


> True, if he had a cloth interior it would just get obsorbed into the foam.
> Congrats!!!
> What was the cruising temp, and what did you get for MPG, or do you just fill it up and not worry about it.


well i survived w/o needing a emergency stop, but the throne was a welcome sight by the time i got home :lol:

as for temp, i don't know, don't have a gauge (don't crucify me).

mileage was around 14


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