Quote Originally Posted by mr-natural View Post
L98 that was driven with a stuck thermostat about two miles before noticing the overheating condition. That's two miles after starting the car when it was cold. Now with a new thermostat I can run the car for a few minutes before the white smoke appears and that will happen before reaching operating temperature. When I kill the engine the radiator cap spurts out about 8 Oz of coolant the quickly stops. Seems to me that it's got to be one of the big three: heads, head gasket or block. Is there any reason not to start pulling the heads?
Sorry I didn't give an update sooner. Pulled the heads and brought them to the machine shop which found that my umbrella seals were shot. He wanted to know what lift cam I had and I didn't know since it's a Chevy experimental cam that my engine builder recommended. So I measured the lift at .603" With the umbrella seal smashed too much oil getting down the valve guides. Machinist took about .100" off the valve guide bosses and all is well. EXCEPT FOR THE VERY SELDOM SMOKE I REFERRED TO IN A POST A FEW DAYS AGO WHICH I'M THINKING IS COOLANT BUT MORE NEEDS DOING BEFORE MAKING THAT CALL.