2004 supercharged grand prix with serious overheating problems. thought we found the problem, busted L fitting to the heater core - changed both of them - bleed - still overheating - then replaced the thermostat - the coolant in the overflow started bubbling with something, husband says it was exhaust - now the diagnosis is blown head gaskets with a quote of 1500.00 but nothung definite about the problem. any suggestions. Needing help in Baton Rouge

Well depends on what it does... I have an 05 Supercharged GTP with 135k miles on it... At first my water pump stoped working and started to heat up... about idk 3/4... which thats above normal, until one day my car started to sound like a big Diesel engine, and my temp gauge was all the way to the top and white smoke. It only had those symptoms for idk less than an hour. I replaced the water pump next day, but...in my exhaust tips you could see water mixed with oil/dirt/exhaust residuals, i couldnt tell, and in my engine, where you put the oil had a white liquid and vapor could be felt... I had it running (even racing) like that for about a month, but it lost alot of power and after 4 or 5k rpms started to knock like crazy like when your engine is about to blow... so i opened up the hood took everything out and yes a blown gasket, and that was it...if your lucky like me it might only need the upper gasket and no head work... but check for symptoms if its only the upper gasket i would say that is about a 300 dollar job not 1500...

I believe there is a chemical that you can add to the radiator to indicate whether the head gasket is blown by changing to a certain color, but a qualified mechanic should be able to tell if the head gasket is blown by doing a compression test on the engine, if he can't I don't think I would let him touch my vehicle,if the head gasket is blown it will need to be repaired......hope this helps....cheers