Excesive oil leak on valve cover?
Thread Starter
Seasoned Member
Joined: Apr 2015
Posts: 375
Likes: 2
From: Denver, Colorado
Year: 2000
Model: Cherokee
Engine: 4.0
Hello gents, so that air vent thing on the front of my 4.0 is leaking a rather large amount of oil. So much that I can see it seeping down the cover towards the oil cap. The grommet and tube were replaced back in July. So why is it leaking so bad. There's also oil that ends up in the air box. A small amount but still significant. Not the best pics I'll get some in the sum tomorrow. Thanks.
Senior Member
Joined: Sep 2014
Posts: 739
Likes: 6
Year: 2012
Model: Grand Cherokee (WK)
Engine: 3.6 V6
Does your valve cover have the flutes inside ? Check out Cruiser54's list there is a mod that could help with the oil in the air box. I think I posted pics from mine too.
Senior Member
Joined: Sep 2014
Posts: 739
Likes: 6
Year: 2012
Model: Grand Cherokee (WK)
Engine: 3.6 V6
Senior Member
Joined: Sep 2014
Posts: 739
Likes: 6
Year: 2012
Model: Grand Cherokee (WK)
Engine: 3.6 V6
I cannot say for certain whether or not the 98 does but your valve cover looks like mine so it might. You cut the flute shorter and drill a hole in it and it is supposed to make them less susceptible to capturing the oil which allows oil to get back to the air box.
Senior Member
Joined: Sep 2014
Posts: 739
Likes: 6
Year: 2012
Model: Grand Cherokee (WK)
Engine: 3.6 V6
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Senior Member
Joined: Sep 2014
Posts: 739
Likes: 6
Year: 2012
Model: Grand Cherokee (WK)
Engine: 3.6 V6
The other thing that could help is replacing the grommets in the top of the valve cover but I don't see that helping with the air cleaner box issue. Good luck with it.
CF Veteran
Joined: Feb 2010
Posts: 12,367
Likes: 23
From: Oroville, CA
Year: 1995
Model: Grand Cherokee
Engine: 4.0 with all of the noise and clatter
Replace the rubber grommets on the top of the valve cover. They get rock hard after a while and start leaking. You should replace the vent elbow and CCV elbow too. You might have to pull the valve cover off because those grommets are pretty difficult to get out without pieces of them falling down into the engine.
Thread Starter
Seasoned Member
Joined: Apr 2015
Posts: 375
Likes: 2
From: Denver, Colorado
Year: 2000
Model: Cherokee
Engine: 4.0
Replace the rubber grommets on the top of the valve cover. They get rock hard after a while and start leaking. You should replace the vent elbow and CCV elbow too. You might have to pull the valve cover off because those grommets are pretty difficult to get out without pieces of them falling down into the engine.


