I'm trying to figure out what's wrong with a friends car for him...... Here goes......
95 Lumina - 3.1 MPFI - 101,000 miles on the clock, appears to be pumping exhaust into the cooling system.When the engines cold it has 165 - 170 PSI compression in all six. As soon as the engine gets warm it starts pumping all it's coolant into the bottle. This starts happening before the engine reaches its normal operating temp. after the thermostat opens, the temp continues rising until it pins the gauge and pumps all the coolant into the bottle. The fans work and we've tried
3 thermostats, that's not the problem. The upper radiator hose is getting smoking hot when the thermostat opens, at about mid temp gauge. I just got the engine smoking hot and did a hot compression check. Again, all holes at 165 - 175. I was figuring it was a cracked head which would pump exhaust into the cooling system after the head got hot enough to expand and allow a crack to open up, and then seal when cool, BUT, good compression seems to be proving me wrong. A burnt head gasket would have the problem cold as well as hot I would assume....... I'm pretty sure it's compression in the cooling system as I put my Stant radiator pressure tester on and started it up cold. Just as the thermostat opened the pressure gauge started rising until it pinned. This car is well cared for and belongs to a good friend who can't afford to throw money at it until it's fixed. In other words, it needs to be fixed right the first time. Can someone point me in the right direction ?????Thanks Brian...........