I just bought a cherokee 1993 with he 4.0 motor. The guy mentioned that it was losing coolant and it had a noticable shake at idle. Compression test showed 60 psi at the front formost cylinder and unlike the other cylinder the front valves in that cylinder were very clean indicating to me and my friend that coolant was getting in there and cleaning it up. Strange though we didnt see a definite cut or break in the head gasket itself. We sent the headout and it came back good. They machined it etc. Just wondeing what they check for and how good they are at determinig if the head is bad, when you send it to one of these machine shops? Ill be putting it back together in the next day or two and wanted to know if there are any things I should look out for before I put it back together. It also has a noticable slight knock at idle warmed up. When went to check the vibration dampener it was clearly loose and able to be moved by my hand. the key way broke off and the bolt backed out so I think I found my knock. Also there was no coolant in the oil. but it has been losing it. I guess what Im asking is it possible the head gasket was bad or the head warped and would a head gasket cause the low compression and shakey idle..all other cylinders were 130 psi even after a few cranks. The front one never came above 60. When I close it back up should I use any sealent. I read one post where the guy recomended putting some sealent in the first left head bolt where it goes throught he coolant passage. Does anyone know anything to this and why I would want to do that. Also do I put any permatex around the head gasket itself...I know im asking a lot of questions but Im looking for any help to these questions that I can get and I appreciate any replies. Im hoping to luck out on this truck and have a daily driver for a few years if Im lucky
Sincerely
Mike
Long Island