Pontiac Repair: 2001 Grand Prix Temp Gauge moves HOT, intake manifold gasket, upper intake manifold

Question
3 months ago had my grand prix checked because temp gauge is running hot. Mechanic said just needed coolant...that was a little embarrassing as i know nothing about cars! Now its doing it again and my heater just blows hot air for a minute then goes cool.  I checked the coolant return (when car was hot) and its a little low...mechanic said last time this car burns thru coolant and to check when cool. think it is same fix? Trying to avoid another bill if i can correct it.

Answer
Hi Mike:

Just adding coolant is not a fix to the problem. There is a leak in the system somewhere.  What engine is in this? if it's a 3100 V6 chnaces are that the lower intake manifold gasket have failed and hopefully it's just leaking the coolant outside the engine. When the gaskets go bad "really bad" they start to leak coolantinto the engine which is bad. If this has a 3800 V6 chnaces are that the upper intake manifold gasket and failed and it's leaking coolant out of the engine. When these go reall bad they leak into the engine so bad that it will not even crank over that is REALLY bad. I would have it looked at again and get it fixed before is becomes a major issue. Just topping off the coolant is not a good fix. Also never chek it HOt only when the car is cold and has sat overnight that way you don't have any chnace of burning your self with hot coolant. Good luck :}