OK so i have a 1994 camaro z28 Lt1 and it was overheating, so i replaced my old electric water pump and put a new one in. the old one was all messed up and i also replaced the thermostat..and it worked fine for about a weekend. but now i can drive it and while the car is on it is fine. but when i stop and turn it off and let it sit for about 10 mins when i start it back up the heat goes way up into the 270range..but if i let it sit for about an hour and a half and let it completely cool then its fine and i can drive it no problem..does anyone know wtf this is? ive never heard of this problem before ..thanks guys

 

When mine sits still, the temp rises on the gauge, cause the fluid is not circulating through the motor, and staying right on the temp sensor in the Head. It runs at 195, I get out and let it sit for a few minutes, it will read 225. As soon as it starts, it will go back down to 195.

 

What thermostat did you put in? a stock one? I just put in a 160 yesterday and the first time I drove it stayed nice and cool at 170 and then I shut it off for ten minutes, came back out, and the tempeture while I was driving slowwwwwly was going up until it hit 210-220, I started getting worried and then (i have a tune but my fans still come on at 220) the fans kicked on and it started cooling. You bleed the system? You just have to get a tune to make your fans come on earlier so it can't get so hot.

 

Hi Folks
Replace your Radiator CAP - it may look OK but if it has years on it, it isn't working correctly and not holding the pressure.
Thanks
Bill

 

good suggestion!
it's the most quick and eassy fix but can cause alot of problems!

 

I have the stock 180 deg. Thermostat as far as I know, and my Fans canstantly run. I also have the AC System removed, no Condensor infront of the Radiator, so that helps with cooling.

 

where can we buy a nice chromey cap with a nice chevy logo or whatever?

 

i have a 160 thermo..and my cap is brand new..but it still overheats when i restart it.. the radiator is new too..

 

you have a leak somewhere. hmmmm. Check your hoses. Might have to pull out the fans to get some more room to work with.

 

I would ENSURE the fans are working. Find out what they are set at and find out if theyre coming on when they should. When they come on will be a reflection of what the engine temp switch on the near the water pump reads (if it's working correctlly) not the gauge on your dash which goes to the side of the head and is 15 or so degrees of from what the computers see's (also baring your das gauge and sender is good) If the fans arent working and the temp switch is good check the relays and fuses. If those checkout try to rule out the fan motor itself. Also bleed the heck out of your system to get those air pockets out.

 

when you bleed the system, use the bleeder screw on the water neck...ONLY SCREW IT OFF HALF WAY! Do NOT take it out and do NOT let it fall. That will bring you into a world of pain, searching and suffering and 30 dollars from the dealership. Believe me. I have been thru it.

 

yeah, i almost lost them before..i was bleeding it when it was really hot and it almost blew the screw off..thanks guys all try it and get back to ya

 

i just did all of this to mine today too. i replaced the 2 heater core hoses and it was a PITA. it ran pretty hot when i was done, but once i let it run for awhile, let it cool, then started it up again and double checked everything it did really good. i also used some redline water wetter and bled the system so its pretty happy now. stays under 210 most of the times until it sits and idles. make sure your system is bled well, the fans come on, and you aren't leaking anything. if those are all ok, then you may have bigger problems

 

well i took it to a shop around here and he suggested putting on a restrictor in the place of a thermostat because the thermo is causing bubbles? does this sound like crazy cause ive never heard of these before..

 

Hi Folks
I agree with you, that sounds crazy - I have never heard of that. Running without a thermostat would cause problems. One of three things: system has air in it - you did not bleed it completely, cracked block/head or blown head gasket, and/or leak in the system - hose. Under pressure, no way can there be air unless the pump is causing cavitation in your water pump.
Thanks
Bill

 

i had a problem like this yesterday. I turns out the plug on the 1st fan was loose and the fan was not comming on. replaced the connector and it works great now

 

if it was a head gasket wouldnt it overheat the whole time that i drive not just after it was turned ofF?