TeamThrash

I have a 95 Cherokee with the 4.0 and about 175k mikes on it. I can drive around town and on freeways with no issues and I have no oil leaks. But when I drive up to the mountains my jeep burns a quart plus. I'm in San Diego so it's about a 30 min drive up there, I'm usually in 3rd gear at 3k rpm or 4th at around 2k rpm for most of the drive there. (It's a stick) I top it off when I get there and wheel all day with no issues with oil, drive home and still have no issue. It basically only seem to do it when I'm powering up mountains. Would that be a pcv issue? None of my friends see blue smoke coming out when we head up there.

Fred/N0AZZ

Run a compression test first.

InitialForce

Sounds like blow by. X2 on the compression test.

When you burn oil does your air filter get soaked with oil spray?

cruiser54

The CCV system needs to be intact and not clogged. That's the hoses/piping and grommets from the intake manifold, air cleaner, and valve cover.

Have you ever shone a light into the oil filler hole to assess the sludge build up?

DFlintstone

I'm actually busy and came back and found you.

COMPLICATION. You need to follow Cruisers advice, and also rule out your oil filter adapetr O rings. An O ring leak is independent of crankcase pressure, but the crossover pipe gets hot in your condition, will burn it there.

Going up hill, blow-by goes up. That's combustion gasses making it past the piston rings into the crank case. The front, 1/2 inch vent on your valve cover needs to be free to vent. If that had an aftermarket filter, or any blockage, crank case pressure is gonna make it blow out somewhere. Dizzy, front seal, valve cover.....and at an angle under pressure, the Rear Main Seal. The rear orifice won't be sucking much there with your foot in it. (not much manifold vacuum there with the throttle plate open!)


I'm the last guy to glance at the RMS as a problem, but my new 90 does just that. Blows oil out only climbing my hill, and the common culprits are rued out. I suspect the leaking Oil filter Adapter waz mistakenly diagnosed as a rear main seal issue, then they boogered up the install of the RMS. Now with the oil filter adapter handled, I need to go back to the RMS and clean that up!

TeamThrash

Yea the air filter does have oil on it. I'll do a compression test this weekend. I have the stock air box and filter in it.

TeamThrash

I haven't looked inside any hoses or the valve cover, but knee a year I have a full service done on it and have the oil system flushed. Also if it was an o ring issue, wouldn't it leak when it was just sitting there too? I have a company vehicle so my jeep sits in the same spot for a few days at a time and there's no drips anywhere. I'll look into the hoses and all that. Thanks for all the advice!

InitialForce

Make sure your ccv lines are not clogged and the fittings in the intake manifold are clear. If the intake side is clogged it will look like you have blow by when it really isnt.

DFlintstone

No drips anywhere. Well ain't that something...Stick me with a fork, I'm done! Same "condition" as me but mine does drip.

IN Cruisers tips there is a valve cover mod to help with oil in the airbox. Did you do like he said and check for sludge?

On Fred's lead...Google wet, dry compression test. I use a section of clear vinyl tubing to blow a couple of tablespoons of oil in the cyl's after writing down my dry numbers. Great info to have, those two sets of numbers. The tester should be free to borrow.

Hey Pete & Co, valve stem seals would leak under CC pressure without dripping....

madmanmarty

My oil filter adapter o ring only leaked when running and under oil pressure.

TeamThrash

So my ccv line is clear and there is almost no gunk building up in my valve cover. (Surprised for 177k miles on the motor) here's a pic of how my valve cover looks. Ignore the muddy ness. Found some mud a few weeks ago haha

TeamThrash

Oh and the air filter doesn't get soaked with oil, there's only a small part of the filter that has a little oil on it. Nothing too bad I don't think.

TeamThrash

I've tried to edit that last one a few times, but it's not saving. I meant the air filter not oil filter. I wish this sites app worked too

DFlintstone

An Old school tell-tale for leaking valve stem seals. It's hot/up to temp, you have been running it fully. You park. After 20 minutes or 1/2 hr, is there a puff or smoke when you first start it?

You might see a sign that oil that ran down the valve stem is burning in the combustion cylinder. Longer it might have run through, shorter it may not have gotten down in there.