Mechanics

CHEVY COOLANT LEAK

1999 Chevrolet Malibu • 6 cylinder 2WD Automatic • 145,000 miles

I have a 1999 Chevy Malibu LS, with the 3.1L V6 motor. I live in Wisconsin so the car sees very cold winters each year. Just recently I have coolant (dexcool) leaking somewhere out of the left-hand side (coolant reservoir side) of the motor. It is NOT leaking from the reservoir, radiator, or lower intake gasket). I know it is not the lower intake gasket because I had that replaced about 2 years ago already. The leak appears to be dripping off the left side of the engine block. What do you guys think? If you can come up with any diagrams that would be great…it is just impossible to get a good look at the left side of the block with the water pump housing and everything else in the way. The Hanes manual doesn’t give a good diagram of it either. Your help is greatly appreciated!
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Davisn95
November 15, 2010.



The only cooling system component on that side of the engine is the water pump, Could be the water pump itself or the mounting gasket to the water pump. Does it leak while running or when the car has been off?

Tiny
Bschurr
Nov 15, 2010.
The leak is dependent on the motor running. After I park the after driving it lets off a few drips. This is another sign that the leak is not a crack in the reservoir or radiator. It happens after flowing through those. If it means anything I noticed the dripping has slowed down. Last weeks it dropped a large puddle emptying the coolant reservoir. After that I filled it back up and since then has only been letting off a handful of drops when parked after running. I always keep a very close eye on the coolant levels before driving and while driving I keep a close eye on the engine temperature. It never overheats.

Tiny
Davisn95
Nov 15, 2010.
The proper way to diagnose a leak is to pressurize your system and look for the leak.

Pressurize the system to the psi rating on the reservoir cap. If you can't see the leak from the top, then jack the car up and look from the bottom.

Also, just because the intake gasket was replaced doesn't mean it won't leak. Not saying that's what I think it is, but don't rule something out until you've tested it.

Ernest Clark
Nov 16, 2010.
Thanks for the help guys. I found the leak, it was the water pump gasket. The gasket was ate apart on the bottom side. I wound up replacing the water pump as well since I had it apart anyways and the new pump came with a gasket.

Tiny
Davisn95
Nov 29, 2010.
No problem. If you need anymore help, just let me know.

Ernest Clark
Nov 29, 2010.