My coolant temp shot up to 260* this morning. This was after about 22 miles of highway driving. I pulled into a parking lot. I did not see any leaking fluid anywhere. The reservoir has coolant in it (full at a hot temp). I let the car idle for a few minutes and the temp drops like a rock to 220* and stays there (oil temp is around 217). If I try to drive it at all, the temp shoots straight back up.

I did race the car the last Saturday some NA and nitrous runs (ran some 10.90's @ 135). I did drive home (after racing) 40+ miles with no problems.

The car is not misfiring, no leaking fluid, the fans are on, ... What else do I need to look for?

Is my thermostat stuck? Water pump?

Thanks.

 

...did you open the cooling system for any reason? You could have an air bubble that is trapped and preventing the pump from curculating water ...this happened to me once with an LT1 car after i changed the antiffreeze...

Take the cap off and start the car...if antifreeze is curculating let it run for 10 minutes with cap off...this will bleed any air out...

....if no water is curculating, you probably have a bad pump...

 

..what does the exhaust smell like - antifreeze? if yes, you blew a head gasket or worse...nitros is dangerous stuff...

 

Is the oil milky?

 

Nitrous is "NOT" dangerous stuff, <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" /> only for rookies who have no clue what they are talking about or doing! <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />

Start with fan belt first, make sure it is not slipping, then make sure the radiator is not being blocked by road debris like a piece of cardboard or plastic bag, then check that fans are coming on properly, then from there check for bubbles in the radiator, (bubbles perculating in the radiator would be a sign of leaking head gasket and or a cracked head)!

Good luck! <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

<small>[ March 21, 2003, 11:53 AM: Message edited by: Orange Krush ]</small>

 

Make sure your air dam is still on. If it's hanging or if it fell off, it will overheat on the highway.

 

Thanks for the replies. I did not smell any foul odors when the car was idling.

I will check the oil and check for debris.

Can I run the car with the coolant cap off? I thought it was under pressure? I have a 2001 vette.

 

...last time i checked, our cars do not have fan belts...only a serpentine belt that drives the water pump and other accessories...the cooling fans are run by twin computer controlled electrical motors (is this GM high-tech or what!)...

...anyway ...i still think nitros is potentially a cause of blown head gaskets, burned valves and pistons, etc...sometimes the damage does not show up until days later...

...hope you cooling problem is better now....

 

...yeh you can run the car with the cap off ...just dont open the cap until the car is cool (30 miniutes or so)i assume you knew this from reading the label on the cap!

at idle you can run the car all day long without a cap....just don;t drive around with it off...

the older LT1 cars have a bleed screw in the system to evacuate trapped air ..the LS1 cars do not, however...PITA

...how much nitros were you spraying? ..anything unusual happen during the runs?

 

Well you can't leave the cap off forever.

If you have to top off coolant every morning, and you a lot going into overflow (like after driving and coming to a stop) then you might have toasted a head gasket

 

I had it towed to a shop. The guy said he used some test kit to check for hydro-carbons in the coolant, and that the test was positive. Plus, he mentioned something about there being too much pressure in the tank?

Anyway, sounds like a blown head gasket?

Can I pull my heads (01 vette) if I have head studs? I have heard there is not enough room. The whole motor had been out of the car when it was put together.

Thanks.

 

I have never done heads on a C5 but it looks like they would easily come out the top.

You can pressure test the cooling system and see if it's losing pressure.

 

Combustion pressures created by nitrous can cause head to lift and allow pressure to enter cooling system. This can also leave path in gasket for coolant loss or pressurization(leakage in either direction). I believe in head studs and elevating torque figures to help eliminate problems, but head thicness and flatness play a role in good seal.