Mangabobb

hello everybody I'm in need of some assistance, I have a 2006 c6 LS2 and I'm having some trouble with the car. So it all began about a week and a half ago when I was washing my car smoke started coming out the hood and then I realized the car was overheating and this was because of a bad thermostat that I later replaced. But before all this the at car was running like a dream and now after I replaced the thermostat and refilled the coolant, the coolant gauge keeps spiking and going crazy from 31 to 87 back to 47 etc. anyways I have ruled it that it is not the gauge because the little speedo screen reads the same as the gauge and I have tried burping the system but it doesn't work right still. I have noted that when the cap is off when burping the system the gauge seems to be reading correctly and there is no spiking as it stays around the 95-99 degree area as it should at operating temp. Can someone me tell what is going on please.

UPDATE: I forgot to add that the "CHECK COOLANT LEVEL" sign pop up on the little screen for little while then goes away and comes back randomly, then I check if the coolant level is down and it's still full.

BlindSpot

likely you still have air in the system.

Start engine. Turn heat controls all the way up to maximum. Take the car for a drive to reach op temps. Drive normally but make sure you attain a steady 3k rpm for about two minutes.

Bring car home. Let it cool down overnight. Now check fluid level cold. Top off return heater controls to normal or ac.

Mangabobb

Ok thanks buddy I'll try this when I get home and I'll update you tomorrow but if that doesn't help I have an appointment with the dealer at 11am tomorrow. I'll update with what's going on thanks for the reply.

Vet Interested

It does sound like trapped air in the system. Chances are you will save a $$$ trip to the dealer!

Mangabobb

Ok guys, so I did what you guys suggested it didn't remove the "air lock" completely but now the car operates around 80ish and spikes up to the high 90s every now and then with the random "CHECK COOLANT LEVEL" sign. I didn't end up going to the dealer and I'm going to try this method again to hopefully clear the whole system of air pockets and I'll update again tomorrow with the final status of the car. Thank you for your help everyone.

Dutch08

I agree with all of the comments. (My 2-cents)Park your car nose high a bit and try it again and don't forget to turn on the heater.

Mangabobb

Ok guys so everything starting working fine the car was running around 80ish and then I parked ina parking lot for about 5-10 mins letting it idle then it started smoking again shut it off instantly but there was already a pool of coolant on the ground by then and it overheated again I don't know what to do should I run without a thermostat or any other suggestions?

BlindSpot

Sounds now like you have a leak. Where is it leaking? Second question - are you sure you have the correct thermostat in? LS2s are different physical sizes than an LS3, but they are OFTEN mixed up and either purchased or sold incorrectly. They are so close that, if it's your first install, you'll think it is correct, but either tstat in the wrong engine will leak and/or cause overheating problems. 80c is on the cool side, but not unusual if you were parked and idling, but sounds like it idled a while and you might have lost track of the temp before seeing the steam.

Mangabobb

Hey buddy, it wasn't leaking from anywhere because when I went to start my car this morning there was Nothing on the garage floor but it leaked of overflowed out the overflow tank from that little black tube leading to the bottom of the engine bay. As for the thermostat I'm not too sure I went to a general parts store and they searched up by car type and gave me that part, it's was the motorad brand I believe but I wouldn't be able to tell you for sure. The car is at the dealer now just because I don't want to take any more chances of it overheating and messing the motor up, should I tell them to check if the right thermostat is in there?

Mangabobb

And it was idling for an absolute maximum of 10 mins (maybe 2 full songs) after a 15 min drive from my school to a fast food restaurant and back

Mangabobb

Ok so I got the car back from the dealer, and they said there were no codes, leaks or anything mechanically wrong with the car so what they did was re-program the computer just in case. They charged me about $56.00 and the gauge was still going up and down not as crazily anymore but still not constant so I'm going to try relieving the system of any air that may be left and see what happens.