4.0 ccv issues
Thread Starter
Newbie
Joined: Nov 2015
Posts: 13
Likes: 0
From: Central Washington
Year: 88
Model: Cherokee
Engine: 4.0
Ok..I've read the threads...talked to friends...been to the parts store.
So here is my issue...I have an 88 XJ the front vent elbow broke so i replaced it with a breather cap...shouldn't be a problem right?
Now I have oil all over the valve cover..STOP! I have checked the rear ccv and it appears clear (I blew through and no obstructions)...
I have pulled off the breather cap and started the engine to see if there was any vacuum pulling through the system...NO! there is vacuum at the manifold but no pull...what could be causing the positive pressure in the valve cover to push out oil.
So here is my issue...I have an 88 XJ the front vent elbow broke so i replaced it with a breather cap...shouldn't be a problem right?
Now I have oil all over the valve cover..STOP! I have checked the rear ccv and it appears clear (I blew through and no obstructions)...
I have pulled off the breather cap and started the engine to see if there was any vacuum pulling through the system...NO! there is vacuum at the manifold but no pull...what could be causing the positive pressure in the valve cover to push out oil.
Ok..I've read the threads...talked to friends...been to the parts store.
So here is my issue...I have an 88 XJ the front vent elbow broke so i replaced it with a breather cap...shouldn't be a problem right?
Now I have oil all over the valve cover..STOP! I have checked the rear ccv and it appears clear (I blew through and no obstructions)...
I have pulled off the breather cap and started the engine to see if there was any vacuum pulling through the system...NO! there is vacuum at the manifold but no pull...what could be causing the positive pressure in the valve cover to push out oil.
So here is my issue...I have an 88 XJ the front vent elbow broke so i replaced it with a breather cap...shouldn't be a problem right?
Now I have oil all over the valve cover..STOP! I have checked the rear ccv and it appears clear (I blew through and no obstructions)...
I have pulled off the breather cap and started the engine to see if there was any vacuum pulling through the system...NO! there is vacuum at the manifold but no pull...what could be causing the positive pressure in the valve cover to push out oil.
i always wonder what was going on b4 it broke? was it all normal?.
can you get it back to the original state?
CF Veteran
Joined: Feb 2012
Posts: 1,206
Likes: 2
From: Southern Oregon
Year: 1990
Model: Cherokee
Engine: 4.0
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CF Veteran
Joined: Feb 2012
Posts: 1,206
Likes: 2
From: Southern Oregon
Year: 1990
Model: Cherokee
Engine: 4.0
Originally Posted by cruiser54
LOL, PNW, you saved me a lot of time!!!
On another note, I recently came across another thread on here about swapping out the valve cover with one from a newer 4.0 with better CCV grommets. Basically 91+ has better CCV fittings, but every couple years has something a little different. Here is the post


