Well, the truck had a blown head gasket, and had a rod knocking. The guy that owns the truck had been driving it for about 500-600 miles like that. The head was warped. Had a .004" twist in it at the water neck. I belive that it was blown in another spot just over the #5 , and it galled the everloving piss out of the piston. The cylinder looked like crap, and I thought it would have to be bored. Luckily enough though, ithoned out really nice. The knock in this one was alot louder under the truck. Try to determine where thre knock is coming from. I have heard them "knock" in the top end before, and it turned out it was a broken pushrod.