Expert: autohelp - 12/10/2008

Question
why is my 1999 cadillac devielle still over heating i have change the radiator,water pump and thermostat i am loosing colant but can't tell where its going no signs of water in the oil no smoke out of the exhaust i have full power

Answer
The most common fault is small leaks in the head gaskets that is allowing small amounts of coolant into ALL of the combustion chambers due to faulty head bolts that are loose due to threds being stretched in the aluminum engine blocks.

This IS very common and usually does not show any signs of white smoke from the exhaust because ALL the cylinders are receiving small amounts of coolant and burning it off.

Check the torque on your head bolts and don't be surprised if they are loose due to the threads being stretched in the block.

PROVIDED you do NOT have any external leaks on the ground.