jhall

I am no mechanic by any means. I can take apart and put together very well though. Troubleshooting is an art that I believe takes knowledge. Anyways, my 1990 4.0 inline 6 has oil build up on my exhaust manifold inlets, throttle body, air lines, and air filter. I'm replacing my head gasket and have it all disassembled. Before I put it all back together wanted to find out if this is a serious issue and how to stop it. I got new clean airlines from the junk yard to replace.

kjc

I'm going to guess you mean you have the valve cover off as opposed to the actual cylinder head, and are replacing that gasket? Good idea, they do tend to leak over time. Use a good Fel-pro gasket, not some crap cork or cheapie brand. The oily air filter is likely caused by the ccv (crankcase ventilation orifice thingy) pardon my techie lingo there Think PCV on most other cars. On your Jeep, it's the little elbow shaped piece that goes into the valve cover towards the rear. This little orifice gets clogged and causes the hose at the other end to suck oil into the air filter. I couldn't find a replacement for mine, so I just rigged up a tiny inside diameter piece of hose for it. You might find one, I didn't really search very hard. If I mis-read your post, just ignore me

F1Addict

Well, jhall, what you need is a new vacuum harness (available from NAPA for $23) which not only includes a lot of sparkly vacuum lines but also the big rubber elbow that plugs into the front of your valve cover. The rear grommet is available through Dorman's Help! brand for $3. Replacing those two things should resolve the issues you're experiencing.

jhall

@Kjc, I did change my head gasket and have the actual head removed. I just wanted to make sure that it wasn't anything else inside the engine before I closed her up. I removed the tube from my valve cover and sure as a turd, clogged.Thanks do the help.
@F1Addict, thanks for the help as well. Just purchased new ones. Thanks for the tip. I pulled one off of a jeep in the scrap yard and went ahead and bought one from your advice to make sure there are no clogs.

jhall

While we're at it, is it okay to spray decreased all over my cylinder head and pressure wash it off with a heated pressure washer to clean it up?

scottmphoto

While you have it all apart, do the valve cover mod (search on here for it). That, along with the new CCV parts will stop this from happening.

cruiser54

Post 25 in my link. Don't put the valve cover back on without doing it.

Get these 3 things from Napa:


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



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.



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



Revised 03-19-2014

XJwonders

What about a 99 valve cover?

cruiser54

I wouldn't own one of those 99 pieces of ****.

JK. They don't have the issue. LOL.

XJwonders

i can see why u wouldn't want to own one.... There's nothing u can do to it and that's less work. I'm betting that's what you don't like. HA

cruiser54

I had a 99 parts Jeep. Got the 8.25 out of it for the wife's 88. And a ton of other stuff.