Fast coolant leak

TIMLEIGH

MEMBER
2004 PONTIAC GRAND PRIX
3.8L
V6
2WD
AUTOMATIC
215,000 MILES

First off this engine is the super charged engine. Car started leaking coolant on my short drive from work to home and noticed heater wasn't heating good inside because coolant wasn't making it to heater core. It was going out on to street and my driveway. Never came close to over heating. I checked the heater core the heater core hoses no leaking there. Checked the coolant bypass elbows which I know was a problem on this engine. They had been replaced at some point with metal ones and were not leaking. I went ahead and changed them again with metal elbows. Checked water pump up and down no leak or noises or free play in bearings. Also checked thermostat housing and all hoses on cooling system. Leak is pouring onto oil filter and that's all I can see from up top. With engine cold and off I can pour coolant into radiator and just comes out on passenger side back corner of engine onto ground like a freeze plug popped out. Also the intake manifold is not leaking like many people have said this engine will do. Oil is a good color not milky. Car runs great and no smoke coming from exhaust.

5 Replies

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

Okay, so it sounds like you have a good handle on what is going on. I don't have the vehicle in front of me, so the first thing that I would do would be to determine where the coolant is leaking from. If you are unable to determine this, the best way to do this is by doing a coolant system pressure test. Here is a link below explaining how to do that:

https://www.2carpros.com/articles/radiator-pressure-test

Please get back to us with what you find out and we can go from there.

Thanks,
Alex
2CarPros

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Saturday, January 4th, 2020 AT 4:17 PM

TIMLEIGH

MEMBER
3 POSTS

Thanks for responding to my problem. I will watch video and do a pressure test on it and get back to you. Thanks again.

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Saturday, January 4th, 2020 AT 5:28 PM

KEN L

MASTER CERTIFIED MECHANIC
43,047 POSTS

Hello,

This guide can help as well:

https://www.2carpros.com/articles/car-is-leaking-coolant

Please run down these guides and report back.

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Wednesday, January 8th, 2020 AT 10:45 AM

TIMLEIGH

MEMBER
3 POSTS

Finally got a chance to really get into where the coolant leak was coming from. It was the bottom of water pump. The gasket blew out. The bearings and impeller were still good and working but was pumping it out down front of block where I and another seasoned home mechanic couldn't see it. He was as amazed as I was at first at how much coolant was leaking. Put on new water pump new battery because it went south at the same time and front sway-bar link that I already knew had separated and now I have my driving to work car back. From top and bottom you could just not exactly see where it was coming from. Just came down onto frame and out onto ground. Everything inside this car works great still at 217 thousand miles and engine and supercharger is still smooth and fast. Heated leather seats and moon roof still work. Anyway thanks again for responding and hope this might help other 3.8 engine owners.

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Sunday, February 9th, 2020 AT 6:51 PM

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello again,

That sounds great. I love supercharged vehicle's as well. I myself own a 1997 Ford Mustang GT with a Vortech V1 supercharger that produces anywhere from 10 - 12 lbs. Boost depending on how tight you wind the engine up. Very fast. Anyway I'm glad you got it figured out and happy motoring.

Thanks,
Alex
2CarPros