I have an 89 wrangler and I had the same problem. It was just a little blow by. The piston rings get just a little loose and let just a bit of oil by them. I am on my third engine. I bought a reman from capitol engines and its starting to do it. If you have a little filter inside where the air filter is I took a piece of scotchbrite pad and put in it. It held it back somewhat. Your engine is fine other than that. I haven't seen a jeep 258 that didn't do it.
89 YJ upgraded with 95 Chevy LT1 small block, NV4500 5spd, tera low 231 SYE, Custom built crossmembers and skids, 2003 Corvette Electron Blue paint, 3 inch custom spring lift with 2 inch shackles, 2 inch body lift, locked 8.8 with discs, 4:10's and 35's, spray lined tub, and a few other unmentionables
I have a 90 and an 85--both with the 258, and both with the exact same problem (despite regular PCV valve replacement). My solution was to just move the PCV breather element to the outside of the air cleaner assembly so that even though the breather element would eventually get clogged with oil, it wouldn't ruin my air cleaner by constantly getting oil all over it also.
Currently an '86 CJ-7 and a '77 CJ-7 Golden Eagle---#4 and 5 following a '01 Sahara, '90 Sahara, and '85 CJ-7....
i have a 93 wrangler and i had the same problem not too long ago. after a lot of troubleshooting i found out that the inside of my catalytic converter was breaking up and restricted the flow of the exhaust so it was blowing back out of the air filter. i went through many filters b/c of this and now i have no problems.
93 wrangler yj, rebuilt I6, 31x10.50s, 3" bl, warn rock crawler front and rear bumpers, air raid tbs, funnel ram air intake system, permatech spray in bed liner, 12000 lb mile marker hydraulic winch to come soon.
Since this is a common problem maybe a detailed description would help everyone out.
Problem: Air filter full of oil or puddle sludge in airbox.
Solution: This happens due to a clogged PCV valve / or CCV hose. 4.2 liter engines use a PCV valve, 4.0 Liter engines use a CCV hose that serve the same purpose as the PCV valve. To solve this problem , you need to remove the valve cover and clean it completely. (Use a soft mallet to break the cover loose - DO NOT PRY between the cover and the head). You also need to clean out the air intakes under the valve cover. They are the two semi triangular fittings under the cover. The one in front is for the crank case breather tube and the one in the rear is for the vacuum line going to the intake manifold. These fittings lead to the holes in the cover where the air goes in and out. If either one is clogged it is the cause of your oil in breather problem. Once this is done, you can replace the valve cover. I recommend a good cork gasket along with a thin "spray on" sealant. Jeep valve covers are a pain to get re-installed leak free. Take your time and follow the torque specs when bolting down the cover. (28 in-lbs. when using RTV only, 55 in-lbs. when using permanent gasket) If any of the hoses look cracked, replace them.
Hope that's enough info
[B]2008 Unlimited Rubicon[/B]
"The weather is here, I wish you were beautiful"
Regarding oil in the air cleaner.
I have been reading this same topic from forum to forum. Everything from removing valve covers to rebuilding motors because of warn or broken parts. Here is a suggestion from a Jeeper that had and fixed that same problem. I now have well over 225,000 miles on my daily driven, rock crawling, 1989 YJ. (With no oil in the air cleaner) On the 258 “Big92Jeep” is correct to say that it uses a pcv valve in the valve cover, but before any serious part removal, try this. With help from the one non-salesperson at Jeep, I fixed the problem with a $1.99 can of gumout. With the engine running you can lift the pcv valve out of the valve cover and put your finger over the end and you should have some serious suction. (While revving the engine) If not, the pcv valve does sometime clog, (When you shake it, it should rattle) To clean he suggested spraying with gumout or replacing (if necessary). But the culprit is usually inside the hose that runs from the pcv valve to the intake manifold. If you removed the air cleaner you would find a split in that (approx ½ inch outside diameter) hose. It connects two hoses together. Inside is a small orifice (approx 1/8 inch inside diameter) that gets clogged very easily. (Trying to remove the two pieces usually ruins the orifice)(It gets brittle)
Before you remove anything, with the engine running, spray gumout into the pcv valve or remove it and spray directly into the hose (keeping the rpms up, so the engine won’t stall) Depending on the severity of the clog a little or a lot of gumout will be used. (Sometimes a piece of piano wire is needed to unblock the orifice) You should notice immediately a difference in the amount of suction at the pcv valve. Reinstall the valve, shut of the motor, open and clean the excess oil from inside the air cleaner. Replace, if necessary, the air filter (this is a good time to install a K&N filter) Remove the little filter, spray it with gumout, replace it and put back all the other parts. This completely fixed my problem. Two years to find and $1.99 and five minutes to fix.
Note: With this line clogged, the pressure inside the valve cover forces oil up through the rear hose into the air cleaner. And with so much oil inside and leaking out of the air cleaner, it leaves room for shady mechanics to suggest some serious $$$ repairs.
That repair was done about 50,000 miles ago, and just to be safe; I spray out that hose along with the carb during periodical maintenance. The problem never came back.
Give this a try. It solved my problem, and at $1.99 for a can of gumout, this might be the cheapest suggestion you’ll get.