I have a black speed rated '96 Z w/elec. moonroof w/22,000 on the clock.
It has never overheated, leaked anti-freeze. Had the coolant system serviced at
Superior Chevrolet in Nov. 2008. They had trouble trying to get air out of the system.
I know that you run the car w/cap off & then open the 2 bleeders on the top of the
motor untill you get a steam of coolant out of both & then close. I was driving & antifreeze
was spewing out of it. Temp gauge was normal, then it started to chug & die... then it
came out of it & I limped it home. I was thinking thermostat... now I thinking it is the
Water Pump since it affected the running of the car. It didn't seem to be hot, which is
weird...
Any ideas where to start ? I'm used to working on '50's - late '80's small blocks...

Thanks,
Mark.

 

Sounds like it could be a head gasket failure. Where is the coolant leaking from?

 

Seems like it's pushing coolant out the Res. tank. I think I might go for the Thermostat
and see if that solves the problem.

 

Well, I drained the whole system, took out knock
sensor & petcock in the block as well. I noticed
drips of water coming from the bottom of the
water pump. I replaced the Water pump with a brand
new one for $162.00 + LT1 specific 180 degree
thermostat - put everything back the way it was &
new Dexcool 1/2 + 1/2 w/distilled water. Ran the
Bad Boy for 40 minutes & bled off any air w/bleed
screws. And there was alot of air in there!

So far only problem has been the fans kicking in.
I pulled both connections out & cleaned - they
seem to be kicking in @ the right times...

I Thank you all for your & help!