My buddies 94 LS which recently had it's thermostat replaced and over heats whenever he's coasting in neutral or at a stop, but goes back down to normal once in gear or higher rpm. Anyone know what it could be or how to fix it?

TIA

 

check to see if there is any air in the cooling system

 

Check to see if the fan is working, it should turn on when driving slowly or stopped and turn off when driving faster.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ckyguy &raquo;</TD></TR><TR><TD CLASS="quote">Check to see if the fan is working, it should turn on when driving slowly or stopped and turn off when driving faster.</TD></TR></TABLE>

it's an electric fan, so becareful, just because it's not spinning doesn't mean it's not working, but the time the temp gauge get's up above operating temp it should kick in. if the fan is working then put a big towel over the radiator cap and slowly open it (it will be HOT HOT HOT and might spray) once you have the cap off, run the car until it's hot then the thermostat should open alowing coolant to circulate, if the coolant isn't right up to the top of the radiator, add more and squeeze the upper radiator hose to releave any air bubbles, if you squeeze it (with the cap off) if the coolant bubbles and goes down, you had an air bubble.

Goodluck..

EDIT: I just noticed that you said the thermostat was just changed, your prob is more than likley air in the system, but there's always the problem that the new thermostat isn't opening. If it wasn't installed properly or it's the wrong thermostat that coudl also be the problem, but check for air first.

 

I would agree with checking first to see about air in the system. You should always relieve the system of any air when changing something like thermostat/hoses, which can be done using the bleeder valve right where the upper hose meets the block. I don't know if that was done, so that would be my first guess.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JMigs &raquo;</TD></TR><TR><TD CLASS="quote">I would agree with checking first to see about air in the system. You should always relieve the system of any air when changing something like thermostat/hoses, which can be done using the bleeder valve right where the upper hose meets the block. I don't know if that was done, so that would be my first guess. </TD></TR></TABLE>

holy chit, you learn somthing new every day.. I had no idea there was a bleeder valve..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JMigs &raquo;</TD></TR><TR><TD CLASS="quote">I would agree with checking first to see about air in the system. You should always relieve the system of any air when changing something like thermostat/hoses, which can be done using the bleeder valve right where the upper hose meets the block. I don't know if that was done, so that would be my first guess. </TD></TR></TABLE>

Any pics of the valve?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ITR 98 1162 &raquo;</TD></TR><TR><TD CLASS="quote">Any pics of the valve?</TD></TR></TABLE>

#10. But I think some years it's not there...

 

Earlier G3's had a bleeder screw, I believe later years did not (not sure exactly when the changeover was, probably 96 with the switch to OBD-2).

But even with the bleeder screw, there will still be air in the system. I have changed coolant twice on my car and lots of air was still trapped in the system even after I got a steady stream coming out of the bleeder screw. You just have to keep squeezing the upper hose until it stops bubbling.

 

mine does the same thing too. i just recenly replace the thermostat, hoses, and radiator cap. it also seems the coolant on the reservoir changes to a darker color and sounds like it's boiling after 40 minutes of driving and will eventually become empty after a few days.
does this happen to your friend's car ITRacer?

 

Watch out for the water pump. If the cars temp goes up at idle, or constant low RPM cruising but then goes to normal when its reving or under load i would get it checked out. If antifreeze is leaking its a sure fire sign of a water pump.
Goodluck to you!