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Weird oil leak, top of valve cover (pic)

C

chad

NAXJA Forum User
Location
lancaster, CA
I have a bad oil leak that from what I've read hear is most likely the valve cover gasket and the oil filter adapter. I've got parts to fix them, but I have another weird leak.
Any time I'm on the freeway or any sustained rpm for more than a few minutes I find lots of oil on top of the valve cover. You can see in the pick that the rear 2/3 of the cover is soaked. It seems to be seeping out of the three ports in the cover, and the fill cap especially. Is there supposed to be a gasket or oring on the fill cap? I want to be able to fix this problem when I pull the cover off to do the gasket.
Any help is appreciated!
Picture0417121145_1.jpg
 
There is supposed to be a rubber gasket on the cap. Go to the hardware store and match the cap with a big rubber washer. I had the same problem on my 90 XJ. Replaced the washer and made sure the CCV and hose was clear. No more leak.
 
Not sure the year you have there, but if I am correct its an 88/89? Renix? The baffles on the inside of the valve cover gunk up easily and cause oil to "blow-by" (can be caused by worn rings too). Anyhoo, after a while the breather hoses front and rear will clog and this will cause the cover to leak out of the gromets. If you search around there are several fixes ranging from swaping in an HO cover to sawing down the baffles a bit. As for the hoses you can either replace them with new (available from napa or the dealer) or use an acceptably sized hard brake line.
Are you getting oil in your air filter? This would be another symptom of the problem.
 
Make sure your CCV lines are clear, including the white plastic orifice first.

While you've got the valve cover off replacing the gasket, do this:

Cruiser’s Valve Cover Mod
Most early and even later Renix 4.0s could be bothered by excessive oil in the air cleaner box. A fix from my old days as Service Manager at a Jeep dealership follows. Information was provided to me from a buddy at JeepTech during those days. I don’t believe it ever came out in a Technical Service Bulletin.
　
Remove the valve cover and turn it over. Next, remove the fluted tubes that are now facing you by removing three screws on each. Chop 1 inch off each of them. Then, about a half inch up from the area where you just sawed them off, drill a half inch hole in the tubes so the holes will face the rear of the valve cover. Clean and de-burr/sand all rough edges nicely, clean with solvent, and reinstall. Don’t be concerned about the chintzy gaskets that will probably crumble into oblivion when you remove the fluted tubes. They can go back together without gaskets.
 
Thanks for the tips guys!
I found all the ccv and vacuum tubes cheap online so I'm going to do the mod and replace it all when I change the vc gasket.
I appreciate all the help!
 
cruiser54 said:
Cruiser’s Valve Cover Mod
Most early and even later Renix 4.0s could be bothered by excessive oil in the air cleaner box. A fix from my old days as Service Manager at a Jeep dealership follows. Information was provided to me from a buddy at JeepTech during those days. I don’t believe it ever came out in a Technical Service Bulletin.
　
Remove the valve cover and turn it over. Next, remove the fluted tubes that are now facing you by removing three screws on each. Chop 1 inch off each of them. Then, about a half inch up from the area where you just sawed them off, drill a half inch hole in the tubes so the holes will face the rear of the valve cover. Clean and de-burr/sand all rough edges nicely, clean with solvent, and reinstall. Don’t be concerned about the chintzy gaskets that will probably crumble into oblivion when you remove the fluted tubes. They can go back together without gaskets.
Click to expand...

I was putting together a valve cover that I'd painted and kept for a few years when I discovered a metal "reed valve" for the tubes. I didn't pay attention to which way the "reed" faces when I had removed it a couple years ago and would like to do this once (as opposed to twice)

does the "reed" press against the "tube" when at rest, or does it work in some way that I can't understand-- with the "reed" facing the valve cover??

...... not to derail the original thread, or nuthin'.....
 
I had this exact same issue with a 90 renix jeep and it was the CCV lines that were the cause for me. Like Cruiser54 said, check these first... BTW I bought the CCV/Vacuum assembly that I have now off RockAuto.com. Best price I could find.
 
Shorty, I'll keep try to take pics of everything when I pull it apart and let you know.

Keith, thanks, I ended up getting a new ccv hose and grommet as well as the whole vacuum line harness from rockauto.com too. great prices!
 
cruiser54 said:
The "reed" should somewhat block the passage.
Click to expand...

it'll "somewhat block the passage" either way-- the definition of "somewhat" is the question. With it pressing against the tube, it blocks most of the air flow. With it not pressing against the tube, it only blocks a bit of the flow.
 
cruiser54 said:
Go for "mostly" then. The factory had a bulletin at one time to bend the "reed" to block the passage more, not less.
Click to expand...

that's what made more sense to me too, I'm thinking that when I took it apart, it was set up the "sensible" way and that's why I didn't bother leaving a note on which way it should be.
chad said:
If I have time I'll try to take pics and do a full write up on it.
Click to expand...

groovy-- if you get time it would probably help out e few forgetful old goats like me!
 
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