1995 Pontiac Bonneville

Engine Cooling problem
1995 Pontiac Bonneville 6 cyl Front Wheel Drive Automatic 143, 00 miles

My 95 Bonneville goes through about a half gallon of antifreeze a week. There is no obvious signs of where its leaking and none of its in the oil. So do you have any ideas?
February 22, 2008.

Use a mirror and a flashlight to look at the bottom of the waterpump, sometimes they will only leak when the engine is running so you dont really see it. If nothing, have the cooling system pressure tested for leaks, and chemical tested for a blown head gasket (just to be safe)

Feb 22, 2008.
There is problem with the Intake plenum. Were the EGR pipe goes through the plenum they develop a leak that only get worse with time. The repair is a new plenum. The plastic degrades from the heat and deteriorates. I have tried the repair kits. It was a disaster. I did not try a new Upgraded model. I went with an OE model. Its been 5 years now. I am seeing signs of condensation under the oil fill cap again and coolant level never really stopped disappearing. Its inherit in the system. Good luck

Feb 16, 2014.