krazynezz

Search isn't working on my phone so please don't harass me about there being several other topics this is addressed in.

I've got oil blowing through the valve to my air filter and am unsure of what would cause this.

89Laredo

I like how you know we dont like repeat topics, but you dont include basic information...
Year, engine?

Assuming 4.0, I would first pull the ccv hoses and make sure they arent plugged up, clean out the orifices.
If it still does it after that, you pry have excessive blowby and need to build a catch can.

krazynezz

My bad half asleep but unable to actually sleep. 93 4.0 sport with 212k on the clock.

Howler_GT

Oily air filter is a common problem.

PROBLEM:
Lack of vacuum inside the valve cover allows oil-laden air to be pulled back through the fresh air tube into air cleaner by the suction from the intake.

CAUSE: CCV orifice gunked up cutting off main-line vacuum/ CCV hose or connector failure.



Large hose on front of valve cover that comes from air cleaner is the "fresh-air inlet"
The rear most hose on the valve cover is the CCV. The plastic elbow is the "CCV orifice" Often mistaken for a PCV valve... no vacuum-activated valve like a PCV, the CCV is merely a metering orifice (basically, its just a small HOLE)

Over time this hole gets clogged with GUNK. Clearing the blockage is the easiest fix.
Old-style orifice turns and pops out (like an oil cap) Elbow is short
New-style orifice is grommeted to the valve cover. Elbow is tall

Refer to pics at bottom of this post (91-older style/94-newer style)

Care must be taken when removing the newer units as the grommet can tend to be hard/brittle making removal of CCV elbow difficult. Sometimes cutting and replacing the grommet is the only recourse.

After elbow has been extracted from the valve cover the opening can be cleaned with a small diameter drill bit (best to use hands w/bit-no drill) and some brake cleaner.
Replace eblow back in valve cover.

FULLY inspect vacuum lines for cracks and/or blockage. Repair or replace IF necessary. Often the rubber reducer that slides onto the elbow fails, so look carefully at it for cracks. Alot of XJ owner throw together a "makeshift" tube using some pices of heater hose and hose clamps. This is the least expensive route as the factory rplacment "tube asseblies are ridiculously priced. BUT if you wish to go the OEM route- TeamCherokee has the best price I have found.

Next you need to look at the vacuum fitting on the intake. Just like the CCV orifice, this too can get gunked up.
Use the appropiate sized socket to remove the fitting from the intake.
Clean any gunk out of the fitting using the same tools used for the CCV orifice.

Use a flashlight and look into the fitting opening on the intake. Of course this should be open but if it isn't, read on.

If the vacuum fitting opening on the intake is also gunked up care must be used to remove the blockage without allowing any of the offending dirt to fall into the intake.
A small diameter (slotted) screwdriver and a dab of CLEAN grease are need.
Use any type of grease. (I use wheel bearing grease) As long as its clean.

Put some grease on the tip of the screwdriver and use it to remove the blockage in the vacuum port intake opening.
The grease should "capture" almost all of the offending gunk.
Clean the screwdriver and re-apply grease. This time make it a fair sized "glob". Now reach down as far as you can inside the hole to get any "leftovers"
Reinstall everything.

Remove the hard plastic tube on the fresh air inlet.
Clean thoughroughly with brake cleaner.
reinstall tube.
NOW: Give the tube a turn until the slight bend that is in it is rotated to the top.
This adds a bit of "uphill" to the hose and gives any "liquid" some resistance.

Replace the air filter.
Clean the air cleaner lid of any nastiness, especially around the freash air inlet port.

You are now "done"

IF your staining hasn't stopped or greatly decreased, let me know and I will give you a write-up on how to make an inexpensive oil separator for the fresh-air intake.

Original prototype in our 91 Laredo.


Current unit in my persoanl DD 94 Sport.

krazynezz

Thank you very much. Amazing write up! Doing oil change today. Will also be doing this.

MrSchaeferPants

That's cool. I checked my air filter when I did my thermostat the other day, and it was pretty saturated with oil, although I assumed it was from the PO over oiling the K&N reusable filter, so I was going to put a paper element that I had laying around on it. The oil looked clean, so I don't think I have that problem, but I think after reading this I'll go ahead and check all those lines mentioned above anyway.