A couple of weeks ago my check gauges light came on so I looked at the temp. and it was reading about 250, so I shut it down. Had it towed home and I looked for leaks and couldn't find any, I wasn't low on coolant, and the thermostat was working fine. So i bled the system and started the car, it idled and drove fine and the temp stayed at about 180. As soon as I shut the car off the coolant started boiling and came out of the resivour. Next I replaced the cap thinking the system wasn't holding pressure. It didn't work, I can do the same pattern everytime-bleed the system, drive around fine, shut it off and it overheats. Anybody have any suggestions?

 

I would flush it and flow test it to make sure there are no clogs or hangups.

Good luck.

 

Pull your fans off when it's hot and feel the radiator, mine was acting like yours and half of the radiator was cold when it was running hot.

 

you should also do a pressure check on your cooling system. easy and most shops do it for free.

 

Geeze man, I had that EXACT same issue with my buddies Camaro, and I diagnosed everything, except the rad cap.

We replaced it and that was the issue.

Did you get a GM cap? Make sure you do. The LT1 cooling system is a low pressure one, at 15 psi max, if I recall correctly.

Get another cap first, from GM. Report back.

 

Thanks for the responses guys. First off, I did replace the cap with a GM cap, and the system is going to be pressure checked on thursday. My buddy says his dealership has a device that checks coolant flow, so if it's a radiator flow problem that should tell us. My other question is- how many RPM's can the stock water pump take? Could I have spun it too high and sheared the drive gear off enough that it's slipping? Right now i'm kind of leaning towards a head gasket problem

 

Don't take it to a dealer. Take it to a radiator shop. They can flow test it for you. They gained 1 second for me. The dealer is probably going to do the same thing and charge you a ridiculous amount. My radiator shop told me it costs 35.00, but if I bring cash its only 20.00. I told him next time, I will bring beer, and he said MGD.

ZMAN

 

My buddy works at the dealership, but does all my work on the side for cheap. At $80 an hour, who could afford the dealer?