OK, I am burnt out, I give up.
Subject: 1979 Z28 350

Problem: You could drive it for days and no overheating problem, then out of the blue it overheats (ie: you park and antifreeze start pouring from the radiator to the overflow to the ground, since it is boiling so much ) .

New 3 row radiator and hoses: installed 12/01
Water pump: installed 7/02, together with bottom hose. The water pump gave in on the bottom little plug.

The thing is still overheating!?! What's up with that? Any ideas?

 

Maybe your thermostat gets stuck once in a while.

 

Oh, I forgot I changed the thermostat when I did the radiator... then put a new one in a few months ago. I even tested the old one and it opened/closed OK .

Something so simple, huh? Yet it is puzzling. I thought it might be the timing, but it runs fine, haven't checked it, but can't imagine that to be it....

If you put one of those radiator pressure caps to pump pressure in there and test, I don't think it will work...as the problem is overheating not leaking

 

ttt

 

just an idea, but carry some gloves with you.. and when it starts getting hot, squeeze the top radiator hose with it running and see if it is getting good coolant flow.... that should at least let you know if it is because of a blockage of some sort....

I would also say check the fan/shoud but you said intermittenly... so for the most part that seems to be out, unless you have an electric fan that is dying...

then you could always try to flush it out. Run a bunch of water through it while it is running and maybe you will clean some crud out...

 

I have the same car and the exact problem.... didn't happen to the last few weeks. New water pump, new fan clutch, new hoses and new 160 thermostat. I about to flush the system, sometime this week cause it does look as if there is some crud in the system. But the thing is its done it twice in the past month. Its not like its overheating though, temp will get up around 200, I'll drive a little ways. Park it, temp will be down around 160-175, but coolant came out the overflow boiling?? And the engine wasn't that hot. I've checked everything you told this guy. Only thing left is flush the system.