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Discussion Starter · #1 ·
I have 90 wrangler 4.2bbl w/ approx 80k miles.
I'm getting quite a bit of oil coming through the breather into the air filter. I've replaced the pcv valve, charcoal cannister, and checked all the hoses - still no luck. Anyone have any ideas/suggestions (without an overhaul on the engine)?
thanks!

 

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A heavier weight oil, or additive might help, depending on your climate.

Also you can route the breather from the air cleaner into the top of a coffee can with lid. Also vent the can back to the air cleaner housing. Keep both fittings up high, and moniter the oil in the can. The can will keep the air filter clean by catching the small amounts of oil coming out of the valve cover, and the line to the air cleaner housing will keep the environment clean by reburning any fumes.

Tim

84 CJ7, 258, HEI, M/C 2100 carb, 5 inch lift, RS9000's, 33x12.5 BFG M/T's, 4.56's and Detroit softlocker, full cage & belts, Xenon flares, Dana 44 rear, GM dual diaphragm brake booster
 
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Discussion Starter · #3 ·
I would begin by doing a compression test on the cylinders. that would tell you if your rings are worn a lot of things could of happened in twelve years. I know some guys disconect the breather hose from the air cleaner and run it to a jug of some sort to catch the oil. sounds like time for a rebuild . I did mine and no more problems . Bob

 

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the jug trick will get you by till a rebuild.. or atleast new piston rings.. do a compression test.. identify your low cylinders.. then squirt some oil in there.. and retest them.. if the pressure rises.. then those are the rings.. that are worn..
what is happening.. is your rings are wearing out.. as they do.. the pressure built up on top of the piston under compression is forced past those rings.. and goes into your oil crank case.. (oil pan area)..
as oil is pumped to the top of your engine.. it is supposed to drain back to the bottom.. but.. you have a higher pressure there vs the top of the head.. so the oil takes the path of least resistence.. out your open hose and into your air cleaner..
so re routing the line to a jug will catch the oil.. it doesnt fix the problem.. dont worry.. it wont just die on you one day.. unless you let it dry up of oil... this will get you by till you can rebuild it.. or replace the piston rings atleast..

http://www.jeepgod.net

If you are allergic to lead, it is best to avoid a war zone
 

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This is a very common problem on the 4.2L 258. Don't feel too bad. Mine's got 86,000 miles on it and it's got a whole lot of blow-by. Like everyone's already said, it's the rings. I don't know about you, but I don't have the money to devote to a complete rebuild just yet and my engine runs pretty strong otherwise. It was driving me nuts because I was changing air filters all the time. Then I rigged up an oil recovery bottle mentioned earlier. You can use any sort of can, I think a Gatorade bottle is a favorite of many Jeepers. I wanted something that looked a bit more permanent though, so I used an old washer fluid reservoir I had sitting around. Of course, I had to plug the hole in the bottom where the old washer pump sat. I stuck two bolts through the firewall from the driver's side right above the charcoal canister and hung the reservoir on those. It sits a little lower than is ideal (below the valve cover), but the hose running to it is mounted high up on the firewall above the wiring harness. It catches all the oil and water and my air cleaner is happy. Just make sure that if you use a large bottle like I did, to check it and empty it every so often or else you could be missing a serious amount of oil in your mill.


TEXAS1AL

84 CJ-7; 258 I6; Restored-to-Stock Condition
 
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Discussion Starter · #6 ·
The same thing happened to me. The #6 cyl. had a compression reading of 10(not 100, just 10). I put in a few drops of oil to see if it would rise...nothing. I'm thinking it's a valve, but that's just mine...yours could have something different. Whatever you do, DON'T PLUG THE BREATHER!!! I wasn't thinking when I was on my way to grandma's house, 150 miles away and I plugged it about half way there because I had it disconnected and oil was spitting out of it onto my exhaust, creating smoke. You can also try a leak down test. This will tell you where the problem is. I'm not EXACTLY sure about how to do this (I have an idea) and I don't want to tell you and then have you screw things up because of me.
So I was 150 miles away from home and needing to rebuild that cylinder. Instead, I decided to be "cool" and drive home with it like that(I added high viscosity oil and did an oil change) and save money to buy a waggie to swap in the engine, tranny and axles. seems pretty reasonable to me because I would have had to spend basically the same amount of time taking the 4.2 out, rebuilding that cyl. and then puting it back in as I would just to buy a 360 V-8, rebuild it, and swap it in place of my 4.2.
Tim

'88 YJ, 4.2L w/Weber 32/36, Procomp 4" w/33 BFG M/T's, TFI upgrade, Stock auto tranny and everything else.
I love bein' a Jeeper!!!
 
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