Asked by Apr 02, 2016 at 02:25 PM about the 2007 Pontiac Grand Prix Base

Question type: Maintenance & Repair

my car keeps overheating, I've already replaced the cooling elbows,
thermostat, and the water pump. However the over heating keeps
reoccurring after ten minutes of driving it shuts down. Both the coolant
reservoir and the radiator are full and i cant see any apparent leaks. I
brought the car to another auto shop and was told that the issue was the
timing cover gasket was the issue. The mechanic said the cause of this was
the replaced water pump, should have replaced a new timing cover gasket
at that time and the old one was loose. Also the cost of this timing cover
gasket was $750 replace does all of this seem to add up?

2 Answers


First of all, I wouldn't jump straight to what this guy is wanting to sell. Here are a few starting points. When the car is cold, pull the oil dipstick. How does the oil look? If it is clear, dark (after a few thousand miles and you're due for a change), then we can eliminate a head gasket issue. However, given what you've described above, I suspect that when you pull the dipstick you are going to find what we call "chocolate milkshake". This occurs when the head gasket has a leak or is fully blown. In these cases, it will cause the coolant to mix the motor oil resulting in what looks like a chocolate milkshake. That is why the car is most likely over heating. I think this "mechanic" is referring to the valve cover gasket, which if the Grand Prix has the 3.8L V6 the timing chain can over time, cause a leak of the valve cover. The water pump and the valve cover/gasket are all part of a normal timing chain replacement however, that shouldn't be occurring under normal conditions on these engines until 150k+mi's. I would have the car towed (MOST INSURANCE HAS FREE TOWING) to another shop that is recommended by someone you know to get a 2nd opinion. A valve gasket is like $10 on Amazon. PLEASE, get a 2nd opinion. If you have questions, feel free to direct message me, or reply here! Best of Luck -sixfootsix_car_guy

1 of 1 people found this helpful.

It's quite likely air trapped in the system. There is a bleeder valve near the thermostat that is used to release trapped air although even that sometimes doesn't work. The system may need to be drained and refilled using a vacuum devise to draw the air out. The whole gasket thing you're being told about makes no sense at all.

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