Well, I got allot of oil in my air box...i noticed it 30 min into my 3hr road trip. It could be blow by and its coming from the front breather tube. But I read that it could also be cause by bad piston rings and I might need a rebuild... My 88 4.0 does have 259k on it. So what's yalls opinion? New elbow joint and breather tube or rebuild?

walk into a jeep dealer and say that. try the cheap crap first
have you read any of these threads?https://www.google.com/search?q=oil+...hrome&ie=UTF-8

I'll check for blow by and check elbow joints and breather tubes. Thanks for the links, I'll remember that next time!

Clogged PCV valve or Blow-by

ALL of your CCV stuff needs to be in good working order, including the rear valve cover grommet.

Renix Vacuum Harnesses
The vacuum harness that attaches to the front of the valve cover and includes the grommet/fitting, and is called the front harness, is Napa part number BK 715-1367
　

http://www.napaonline.com/Catalog/Result.aspx?Ntt%3d715-1367%26Ntk%3dKeyword%26Nty%3d1%26Dn%3d0%26D%3d715-1367%26Dk%3d1%26Dp%3d3%26N%3d0
　
The vacuum harness that is closest to the air cleaner, EGR etc, and is called the rear harness, is Napa part number BK-715-1366.


http://www.napaonline.com/Catalog/Result.aspx?Ntt%3d715-1366%26Ntk%3dKeyword%26Nty%3d1%26Dn%3d0%26D%3d715-1366%26Dk%3d1%26Dp%3d3%26N%3d0

　

The tube from the rear of the valve cover to the intake manifold is part number 715-1365.


http://www.napaonline.com/Catalog/Result.aspx?Ntt%3d715-1365%26Ntk%3dKeyword%26Nty%3d1%26Dn%3d0%26D%3d715-1365%26Dk%3d1%26Dp%3d3%26N%3d0

　

If you feel like making a further improvement and since your valve cover gasket is probably leaking anyway, here's a little trick.

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 guys! That's a ton of great info! I'll be taking a trip to Napa Friday when I get paid and will most likely replace the whole system. And ill be doing that mod! Thanks!

Get the Felpro blue gasket, not the cork POS.

Well I got that stuff at napa today, but I've looked under the hood forever and don't see where it goes? I may be blind but I dont see any but one or two of those attachment places. Here's pics



And this is what I think I need to replace...

I just see where these things go


Any help is sure appreciated, I hate having oil in my air box haha

Time to head back to Napa. You have the wrong part(s). Be sure they reference your exact application.

Did you give them the part numbers that Cruiser provided in post #5? Take those numbers with you.

He's got the right parts, just installing them in the wrong position as he has no refrerence.

thanks cruiser! So thats what's clogged? I figured it would have been one of the elbows on the valve cover.

Previous owner(s) had this thing all sorts of screwed up. The egr solenoid wasn't even attached to anything and the rear valve cover breather tube was going to the egr valve not where it's supposed to be... Man I hope this is what cause that oil in my intake!

are you going to do the valve cover mod? from what I understand is if you don't it will only be a matter of time before that oil ends up back in your air cleaner.

You might be missing a sort of horse-shoe spring bracket that goes on that bolt holding the fuel line. That junction business just clips down into it. For "orientation", that large snorkel looking tube goes to the rear of the air box I think. If you position the junction deal with the tube to the air cleaner, maybe the rest will make more sense.

Mine is broken, but the big tube on the left (in photo), goes to the front of the VC. The right goes to the rear of the airbox.