Mine had an annoying small leak for months from around the filter housing mount. I replaced the gasket..........twice, checked everything I possibly could and eventually found a slight hairline crack in the housing. It would leak when the engine got hot, but I couldn't see the source. Had me stumped until I over tightened the mounting bolts (rule #3 - tighter equals less chance of it leaking) and it got worse and I could actually see the leak. I don't recommend you ever over torque anything, but it worked for me in the end.
Rick

