A buddy of mine recently had rebuilt 4.0 put in his 110. After 100 miles he heard a boiling sound under the hood and upon looking in the expansion tank he found a thick layer of oil in there. No evidence of water in the oil. Could it be the cooling lines leaking into the radiator? Headgasket?

Thanks

:nuke:

:nuke:X2

Start pulling plugs and pressurize the combustion chamber-you'll find it right quick.

Do it before it blows the expansion tank into little tiny bits.

Thanks, we will do that asap.

Well here is what happened. My buddy took his truck to the place that put the new engine in. After examination they said the "film of oil" was a layer of wax or similar substance that the new engine was coated in while in the crate. They said you can only get so much off the inside of the engine and that the residual comes off as the engine heats up. As for the boiling sound they said there is probably a air lock in the system. They will flush and pressurize the system. He should have it back on the road in a few hours. He spent a ton of $$ to have a new engine put in his truck and the last thing he wanted to hear was a blown head gasket. He lucked out.

bs