Just got word from 2nd shop. They say that the PCM is not commanding fans properly and maybe now... blown head gasket. Holy $*** batman!

I have seen one fan and heard fans turn on and both/two speeds. They recommend dealership. So now I'm on the hunt for really good Vette/LS1 tech in the Chantilly, VA area. Anyone out there know one?

 

Yeah, that was the worst case that I didn't want to mention. The fact that you keep seeing air burping out of the expansion tank no matter how much you bleed sure would point to a blown head gasket as do the overheating and sudden onset. sorry man

LS heads are very easy to pull though. Any competent shop can do this work. I'm not sure why your guys think this is a dealer only deal?

 

Thanks again everyone. Got it to "corvette specialists" now and we agree (in short time) that the fans are working OK. Because they turn on at temps listed above in this thread. Others have been using a controller to check fans, and I think they may not have a full understanding of the fan operation. Maybe their T/S guide is not best.

What looks like is not happening, is circulation through the radiator back into the motor. Water pump/stat or blocked rad. Stat replaced with new GM part. Top hose is cooler than hose off water pump, and feels empty. The only time I get the bubbles back into the overflow tank is when I stop the motor and then start to loosen the cap. It doesn't bubble up while motor is running. Plus no sign of gassing/steam/vapor or anything out the pipes. Motor starts fine. So I still have fingers crossed for the heads..

But now battery has gone dead. So I will check/pull the battery out.

I hope to know soon. I'll have the specialists flush the system once we know the problem.

 

Finally a tech that is not hung up on fan operation (0/2 record). Kudos to "Corvette Specialists" Joe. (1/0 record) New techs vs. old techs, old tech win.

Old tech, feels hoses, that's not right. Sees fans running, well.. they work. Man this thing is hot!, I'll let it cool for a while. Old tech just pops hoses off rad, fills rad with water, looks for water, hmm.... How come no water comes out the bottom? I'll fix this! I'll give this dang-thang 60 psi worth of water. Puke, out comes snot, out comes water. Aaah.... that's better. Apparently, some settlement and snot like substance got accumulated in the bottom of rad. Cleared, power flushed, new coolant. All better. Yep, yes sir.... that is one of them there coolant circulation problems. Does all this without computer, mind you.

New techs hook up computer, read guides, operates fans, check fans, fan1, fan2. New tech thinks fans are not operating correctly (but they do run). Maybe computer/PCM bad too. And now cause it's been so hot, maybe head gasket. Holy $**t Batman!!!

So change them fluids on schedule. Don't delay, do it early. Do I seem like a believer yet? Damn Skippy. 95 today, muggy, in traffic, coolant temps... 207 high. HWY speeds, temps 190 So far... back to normal. Woohoo!!!!

Thanks for all good advise from everyone. Cooling systems don't need to be this hard to figure out. I had to pay $$ for this lesson, but on the bright side. I did not make the big mess on my driveway, nor did I kill the neighbors cats and dogs with the coolant run off. I hope this helps someone one day.

 

Glad you got it fixed.

 

It's amazing how things get fixed when you keep it simple! I'm glad you kept changing shops till you got results. It's always good to deal with someone who is confident and stands behind their work. I hope my posts helped.

 

glad you're sorted out

 

yep.... Someone once said "keep it simple stupid". Presidential campaign, maybe?

I got a lot of good help from this thread. Thanks for input and all the good info. Somehow I feel humble and stupid. Damn, I could have done that. But I would have made a large mess with the flushed coolant flowing down the driveway. I think P*$$ the neighbors off too. Face saving rational.

Great forum! Thanks