One cylinder low compression

[etek14]

I have a 8 year old 3.0glp-j engine, use only 2 or 3 times a year. Sits alot and has been in salt water occasionally. Started up this year as usual for a check and found milky oil. No white smoke outnthe exhaust. Maybe a little trouble idling. Compression check shows 80 on the aft cylinder, the rest are 145+, did notice a droplet of water on that cylinder plug. Pressurizing cylinder at TDC revealed air escaping thru adjacent cylinder and exhaust I assume on that adjacent cylinder exhaust port. Could this be a head gasket or something worse(of course it can be worse).

 

[alldodge]

I have a 8 year old 3.0glp-j engine, use only 2 or 3 times a year. Sits alot and has been in salt water occasionally. Started up this year as usual for a check and found milky oil. No white smoke outnthe exhaust. Maybe a little trouble idling. Compression check shows 80 on the aft cylinder, the rest are 145+, did notice a droplet of water on that cylinder plug. Pressurizing cylinder at TDC revealed air escaping thru adjacent cylinder and exhaust I assume on that adjacent cylinder exhaust port. Could this be a head gasket or something worse(of course it can be worse).

The head gasket would be my first guess.

 

[etek14]

Thanks for the reply, gonna carry to the dealer for further diag and repair in the morning. Said possible gasket or valve problem if water entered cylinder

 

[alldodge]

Why not just pull the head off and have a look before you take it in?