I have a 96 Z28, minor mods, listed in sig.

I replaced the opti two days ago with no hitches, everything fell into place well and went together well. The problem is the cooling system, I can't get it to work correctly. I also put a new thermostat in, 180 degrees. After I buttoned up the mechanicals for the opti, I filled the radiator with fluid and opened the bleed screws until no more coolant would go into the radiator. I started the car and let it run, opening and closing both bleed screws until fluid streamed out and there were no bubbles. Problem is, I have no heat inside the car, and the temperature rises pretty fast ( up to 180-200 ) within about 5 minutes. I don't. Know what to do next, I bled the system while on ramps at first, then on level ground. What could be causing this? Massive section of no fluid inside the block? What should I do next?

Thank you in advance,
Tim

 

Did you put a small block Chevy 'stat in it? The LT1 requires it's own special 'stat.

 

Where the bleeder screws open when you filled it? That is when most of the air is purged. An air pocket can make the temp gauge shoot up and come back down just as abruptly.

 

Thank you for your input. I used the thermostat the parts store gave me, it was the same one I was using, just new. It looks pretty standard, didn't know there was a special one.
No, both screws weren't open when I filled it, just the one on the hard line closest to the radiator, I had forgotten about the one onthe water pump until it was already most of the way filled.
Also, when I was cleaning up, I found some type of part I don't remember before. It looks like a deep well socket on the outside, but has two sets of splines on the inside. Any ideas? It was in my drain pan when I got done...

 

Water pump drive coupling

 

That connects the water pump drive to the water pump. Your pump does not work without it installed. #39

 

Ahhh well, yes, yes that would do it! Thank you for your help folks, I just hope I didn't do any permanent damage in the meantime.

 

Spare parts left over after you are done is *never* good. At least you found it!

 

True dat bishop! Just wished I had seen it earlier.
Got the coupler in, and it's cooling just fine now. B of it is, the new opti didn't make a difference in the misfire!
Ah well, fun fun

 

Ignition control module?

 

I hereby nominate Rashiki for the Homer Simpson "DOH!" award of the day
Had a couple of those moments myself
At least your motor's OK

 

I had read somewhere to watch out for that, and had meant to when I replaced my waterpump in september, and still happened to see the coupling sitting on top of my toolbox when I was walking by with the water pump..I could have sworn I left it on the shaft. Maybe they hop off when we're not looking...

 

Yea, learn from my mistake, catalog everything! Even my little magnetic parts trays didn't save me from living in springfield on that one...

Not sure what it is yet, haven't had time to do testing on it. It was breaking up so bad over the entire RPM range when i put it away last fall, i was sure it was the opti. Now it still breaks up, but only under moderate/hard accel, idle seems to be smooth. Time to bust out the multimeter and start checking things!