I'm new to the board, and just picked up a 94 z28. The problem is the car overheats sometimes. The temp moves all over the place. It does this when sitting still or moving. Sometimes it doesn't overheat at all. Also when filling with coolant it starts to push coolant out when car is running (not bubble but actually push coolant out). The radiator also always seems to have room for another gallon or so of coolant. It has no white smoke, no coolant in oil and the car still runs great when not overheating. It also has no leaks, and I have bled the system to death.

 

Maybe you have a failing water pump or thermostat. Have you flushed the radiator lately?

 

I just bought the car. No flush yet. I also left out , that last night I could hear a howl and squeal from engine bay. Does failing water pump make noise?

 

If you just got the car, take it back to the car dealer and let them figure it out. If it's from a private party then of course take on the project. Are you sure your bleeding the coolant correct. There are two bleed screws and this does take time to bleed out the air from the sysytem. Next check your thermostat might be sticking.

Vinny

 

I've spent alot of time bleeding the system, and I've also removed the stat and dropped it in some boiling water, it's not sticking.

 

Check your waterpump. Get underneath the car and see if there is any coolant coming out of the weep hole on the bottom of the water pump. If there is, then your pump is going bad or already has gone bad. Also make sure you have the right thermostat. It is NOT the typical small block chevy one. I believe on shoebox's tech page there is a picture of the correct one.

I had the same problems with my 94Z when I bought it.

Also, the fans don't come on until it is really hot, so you might want to look into a manual fan switch.

Note: If it is your waterpump, be VERY VERY careful when removing it. Try not to let any water get onto the Opti. Or it will go bad too.

 

ok crackhead...get that 180 (maybe even 185) stock thermo out of there...get a 160..as with the 160 get manual fans switches to ensure the 160's capabilities..the fans on our cars just come on way too late (like 228-238) almost at red! open up the radiator cap and look for that shooting stream from left to right (this will tell you if your pump is bad) as for the coolant make sure its a 50/50 mix and add 2 bottles of waterwetter...these cars run hot from the factiry b/c of emissions so cool her down with what i suggested...it worked for me and now my LT1 will never see a temp past 185.
(might want to do a TB bypass when you do all this)
hope this helps

 

Thanks everyone for the help. I just changed the stat, and waterpump. It seems to have done the trick. Thanx again