the cars a 98 firebird that has just had a aftermarket cam installed and tuned as well as a underdrive pulley by a local shop. I put in a new water pump and stock temp thermostat but i cant get the car to stop over heating. The car stays normal temp at idle but gets up to 200-220 while trying to drive the car. Its not losing water out the overflow, theres no white smoke coming out of my exhaust or the smell of coolant, and the oil shows no sign of water in it.

does anyone know what could be causing the car to run hot?

thank

 

are the fans coming on? what temp are they set at?

 

maybe theres air in the system had tha same prob with mine when i changed thermostat

 

both fans are on and i gotten all the air out of it unless it some where else that i dont know abow

 

maybe more information will help, why did you have to change out the water pump and why did you go to a stock thermostat or more importantly what did you replace?

The fact that it only overheats while driving is interesting... So you're saying that if its left at idle for 10 minutes it will not overheat but the moment you start driving it does...

 

that is a good question, you may have to reset your fans if they were set for a different thermostat.

 

The Tsat might be stuck open. Causing the coolant to never cool down enough while under load but can sustain at idle. Try a new t stat or put your old one in.

 

sorry about that my fans are on all time they dont go off untill i trun the car off and the one 190 is the only one i could get at the time but my friend is giving me a 160 to try but i didnt have this problem untill i put in the new cam. The seal went bad in the water pump so i thought that was the problem so i got a new one put in it and it still getting hot. I can let the car sit at a idle for a long time without getting hot but once i drive it it gets hot up to 230

 

How does the airdam look? If it's messed up/missing that can cause some problems.

 

have you checked one of the hoses with a thermostat to see if its actually running hot and not an issue with the gauge or temp sensor? its unlikely that if that was the problem it'd only show hot while driving but i have seen stranger things.

 

no the airdam is on there some ppl ask me about that and i check all of that. umm the hoses were hot like really hot and it hade a lot of psi. umm i havent tryed the temp sensor yet but i put it on a computer and it was showing the car hot as my gauge was

 

its def possible the thermostat is stuck open, that'd actually be my first guess for what its doing. i wish i had more options to give you just in case that wasnt it youd have more things to check, but i dont....

 

if it does fine at idle but gets hot when driving, i would check the radiator. ignore what i said about the fans cause they have no impact when driving. was it a brand new pump? did the old fluid look like ****, maybe clogged the radiator? is the cap keeping the system pressurized? did you bleed the air out of the system?

 

Did you put in a used water pump or a new one, and what brand? Are you running conventional coolant or Dexcool in the car? If you have Dexcool and there's still air in the system, you could run into some problems.

 

when you had the radiator out did you happen to drop a rag or something in between the radiator and ac condenser when you put it back togethor? that would stop airflow to the radiator and make it run hot. Take water and then air and blow through the fins on the radiator and condensor to chean out any dirt and dust that may be trapped in the fins. Did the car run hot before the cam swap? Did you have the heads off to replace lifters? If so maybe you put the head gaskets on backwards and not getting very good flow to part of the engine.

 

I'd call your shop as this was the first thing I thought.

 

it a new water pump and i got it from auto zone this is my 3rd t-stat that i have put on the car and i didnt take off the heads there still the same ones. um i dont have a ac condenser on the car the only thing i can really think that is the radiator. i put a tranny cooler on the car a long time ago but it didnt get hot when i had the old cam in it so i moved it off the radiator to see if that was the problem but didnt change.

 

did they damage the fins on the radiator when they had it out for the cam install?

 

I suggest you drain the antifreeze from the system and flush it out. You might have some build up. But before that, try getting another radiator cap and putting it on your car. It might not be holding the pressure in.

 

this sounds like the problem i was having. i replaced the tstat with the same factory one and drained the coolant and filled it back up with dexcool and cranked it up. let the coolant start flowing with the radiator cap off. once it ran i turned the car off and put the radiator cap back on. turned the car back on and let the system pressurize itself back up and never had any more problems since.