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Now when you turn the key off the coolant still has 16 pounds of pressure to push the itself into the oil!


True, and most of the times it does. But every once in a while you get one of those wierd cases where it takes 20 pounds of pressure to force liquid through the crack....

I've seen it once on a demo head, the prof. pulled it off a semi running topaz with 220K miles on it.

It's just one of those things that I was taught might indicate a bad head.