So I did a cylinder air check for head gasket leak

[king of drummers]

They do not leak into the coolant system, The thing i get is bubbling of oil in the oil passages in the head. Is this normal? If there is no head gasket failure what is causing the over heat condition? I found where I was losing coolant, it was going out the rear gasket of the water pump log and pooling on the trans housing and then running off when the car would accelerate. That's why I could not find the leak with the car together. But now I have solved the missing coolant mystery, what is making this car overheat? The belt was tight. the fans are working. the coolant level up. the thermostat tested good when I boiled it on the stove. Is it possible for this pump to vapor lock or cavitate? Does any one have any suggestions where I should look next?

[STS-in-Nottingham]

Have you checked the surge pipe that goes to the surge tank?

It's a small diameter hose that goes to the top of the surge tank and is designed to purge air from the cooling system, if it gets blocked your engine will overheat, click the link below,

http://www.cadillacforums.com/forums...ght=surge+pipe (Surge Tank Design)

[Ranger]

Originally Posted by king of drummers

They do not leak into the coolant system, The thing i get is bubbling of oil in the oil passages in the head. Is this normal? If there is no head gasket failure what is causing the over heat condition? I found where I was losing coolant, it was going out the rear gasket of the water pump log and pooling on the trans housing and then running off when the car would accelerate. That's why I could not find the leak with the car together. But now I have solved the missing coolant mystery, what is making this car overheat? The belt was tight. the fans are working. the coolant level up. the thermostat tested good when I boiled it on the stove. Is it possible for this pump to vapor lock or cavitate? Does any one have any suggestions where I should look next?

Yes, it is very possible. Follow Nottinghams advice.

That said, "bubbling in the oil passages" does not sound right.