2005 Pontiac Grand Prix coolant leak

ericbau114

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Hello all,
I will try to be as detailed as I can, but I do apologize in advance because I know very little about cars. Here's my problem:

The car is a 2005 Grand Prix and has roughly 250,000 miles on it. We have had the car for a year and a half and havent had any other issues other than complete brake replacement and the transmission is showing its age. The previous owner drove the car for work and put on mostly highway miles.

So, two weeks ago we took our 2005 Grand Prix to a quick oil change place. They changed the oil, the oil filter, and the passenger side cabin air filter. A few days later, we noticed the heat was not working and that the car was running a little hot. I tried to put the heat on full blast to see if it would get hotter and cool the engine, but it did not work. It just blew cool air. Since it was still cold here in Wisconsin, the car did not severely overheat, but I could tell it was a few notches higher than normal. My first assumption was that the oil change place didnt connect something properly and that is why we couldnt pull heat from the engine and that is why we had cool air in the cabin. I now know that was wrong and very misguided.

We took the car back to the oil change place. They confirmed they had done everything properly except top off the coolant. So, the guy put coolant in to the car, as it was empty at the radiator as well as in the overflow reservoir. After letting the coolant cycle through, the engine was back to a normal temperature. At this point, I drove the vehicle to my home.

When I got out of the car, I did not check to see if it was dripping. I know, that was stupid. So, the next day I got in the car and the heat did not work and after 5 minutes the car was running slightly hot. Since snow was melting, it was tough to tell if the car had leaked coolant in the parking lot. I then went and got the pre-mixed coolant and put in half the jug, which almost filled the reservoir. This got the car back to "normal" and drove it while running errands with no problems. When I got back home, I remembered to check for coolant dripping.

I popped the hood and looked for a leak from the top. I could not see one anywhere. I also did not see any coolant on anything else like belts, or the engine, or anywhere. So, then I looked underneath the car. I noticed a slow drip coming from the passenger side. The drip was about once every two seconds and pretty much all of the coolant leaks out overnight. I could not locate the origin of the drip, because there is some sort of plate in the way that blocks my view. It actually kind of seems like the coolant is pooling on this plate and then dripping off the side of the plate.

My question in all of this is where could the leak be located? Do you think it is the radiator even though the drip is not coming from where the radiator is located? Is it more likely a radiator hose? Could it be the intake gasket? What about the heads or a head gasket? Anything anybody can tell me is much appreciated. I am trying to determine whether or not to have someone fix the car or just put it on craigslist as a mechanics special and buy another vehicle. Or if it is simple enough for a complete novice, I wouldnt mind doing the work myself, but I am not optimistic this will be a simple fix. Thanks for the help and please let me know if there is anything I should have included that could help you to help me.
 

EaOutlaw

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Well first thing you or a trained technician should do is pressure test the cooling system.

Using a pressure tester is fairly easy and this should show you or the trained technician exactly where the leak is coming from.

My guess is the leak may be coming from the water pump.

As long as the cylinder head gasket is not blown from overheating the car should not cost to much compared to buying another car.

If you do not know how to work on cars I would suggest taking it to a shop that you trust for a estimate.
 

Xitmnt

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Usually either the coolant bypass elbows or water pump. 2 good places to start
 
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