Reading this thread is very frustrating.

There are a lots of guys that have been trying to help you out here, giving you some great advice, spending their time thinking about your issue.

It would seem to me that you are choosing not to follow their advice, or you have done what they have said and have not posted the results of the wet compression and /or the leak down test.

These guys KNOW what they are talking about, one even offered to come give you a hand if you were near him.

Your next post on this subject should be some results of the leak down test or wet compression test. If you don't understand the tests then please ask for more details about them.

We get that this is irritating and you don't know what the sound is being caused by, but the sound is not the problem it is a symptom of the problem, do the proper tests to find the real problem.

These engines are pretty darn reliable unless they are treated badly. It sounds like the former owner didn't take care of the problem that had caused the freeze plug to pop, a problem that by the sounds of it builds up an EXTREME amount of pressure in the coolant.

I understand that you really don't want to remove the entire engine but don't stress about it, these engines come out easy.

Please do your tests and post the results so that we can help you.

Congrats on the compressor, they come in REALLY handy.