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 stream 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... Hoses all look good, fan comes on -now I'm 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 & '60 BB's

Thanks,
Mark.

 

You need to discover the source of the leak. It's probably the overflow reservoir. Is your low coolant level sensor on? They are really difficult to bleed (reverse flow coolant system). You have to drive it and slam on the brakes and then take off sometimes to work all the air pockets out. Often the air will force its way out through the overflow reservoir causing antifreeze to spill out. If this happens it wont affect the driveablity unless it gets onto the notrious optispark distributer amd then it should buck and misfire etc. Discover the leak first then go from there or repost, because i dont know where to steer you if i dont know what is going on. The bleeder screws need to be left open for awhile when you bleed it to ensure you get all the air pockets out. Keep an eye on that temp sensor. If you want to check the thermostat put it in a pot of water and heat it till it opens...if it does then that is not the issue.

 

where was the coolant coming from? is the water pump leaking? if you got the opti wet it may be toast. not always but thats what happens allot of the time. maybe just wet wires and needs drying or replace. may have had a air lock and had to work its way out.

 

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.
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 replies & help!

-Mark.

 

Good job man, glad you got it working. With a PPIII or other tuning software, you can set the fans to turn on earlier if you wanted to, kinda sounded like you were thinking that maybe.