Should it be air tight? I did the smoke test and it was pouring smoke out from the cap.

 

you just blowing the smoke in ?

 

Should be sealed. The CCV system is designed to pull filtered air in through the air box, not from around the oil filler cap.

 

What?

 

The CCV is designed to pull air in from the air box (filtered air) and not pull air in through the oil filler cap, so the cap should be air tight.

EDIT: I had previously posted that it was a PCV system, however 1996sportXJ corrected me, so I deleted my comments and picture.

 

Um, aren't 4.0L XJs CCV equipped and not PCV?

OP, get a new oil cap

 

The CCV system pulls air from the air filter box through the crankcase. If the oil filler cap were not sealed, it would allow unfiltered air to be sucked in, which should not happen. The dipstick has a rubber seal up top too for the same reason.

 

Thanks for the info guys.

My buddy has one of the auto test smoke machines.