884x4

well I noticed I have a problem...1988 jeep Cherokee xj Laredo 4x4 automatic, 4.0 straight six 262k on the clock
my jeep ticked one day a while back and I thought to myself that it couldn't be oil because I had just changed it 1 month(300) miles ago. sure enough...I checked it. it was a bout 2 qts low...so I added 2 qts. well then I noticed it was 1 qt low when I checked it a couple days ago before a 200 mile round trip. added 1 qt. got home from the trip and drove another 50 miles. checked oil, 1 qt low. I had to add 1 qt of oil,2 days (250 mi) after just adding a qt... I know that's not normal... I had a front main seal leak(fixed) valve cover gasket leak(fixed) oil pan leak-fixed but where the rear u shaped part is I don't think seated right because its leaking right there dripping off the bell housing and oil pan drain bolt(no its not the rear main, it did not leak from there before I changed oil pan gasket)
so I have a small oil leak but theres no way that its dripping a qt every 250 miles.
suggestions anyone? iv never heard of a jeep or car using THAT much oil...

jebmccall

its defnitly possible, my 99 had rings that were so bad i was putting a quart in litterlly every 100 miles.....

i would pull the pan back down and put another new gasket on and reseat it....

884x4

yeah im gonna have to replace that gasket. how do I know if my rings are bad? it doesn't drip oil out off the front valve cover breather

jebmccall

you could do a compression test, but if it is using that much oil you would see blue smoke out the pipe. could be valve guide seals too.

tjwalker

Start with a compression test. With 262k on the clock, you might have an internal issue.

The compression spec for the 4.0 is 120-150 psi with no more than a 30 psi variation between cylinders.

Willys55

compression check will not identify a bad oil ring.

Willys55

I would fix any and all oil leaks first. With 262000 on the engine the oil rings could have lost their tension/sealing ability. Also valve guide seals are more then likely shot by this time.

mr white

What's an oil ring have to do with losing oil

fallenknight308

That area is notorious for leaking. Chances are, you're loosing more oil there than you think. It gets blown back over the trans, flings off on the highway, and burns on the exhaust.
Have you replaced the rear main seal recently? should have if you were already in there. What kind of oil pan gasket did you use? the four piece? they are horrible to line-up during install, and are prone to leakage at each end.
When I fixed my leaks, I used a blue one peice by Fel-Pro, and it was worth the extra few bucks!

tjwalker

This could be a combination of things. Can't assume anything.

Fix all leaks other than the very minor ones, and if you still are using oil at that point, gotta look to internal and that is where the compression test comes in.

A compression test is easy to perform (you can even rent the gauge from some parts stores) and is a good snapshot in time of the internal condition of the engine.

884x4

wow guys awesome advice! I did happen to use the blue felpro on piece gasket but I let the rear ushaped part slip my mind when I was bolting it back up, I noticed it wouldn't stay exactly center it would always go in the pan, I just thought I would make sure it got right when reinstalling but I forgot. the rear main I assume has been replaced cause when I dropped the pan it already had a felpro gasket and those did not come on 88's. the rear main was not leaking and I don't think that has changed. don't fix it if it aint broke right? anyway thanks for the advice guys ill do the compression test after I get it sealed correctly.

884x4

Alright guys, no more oil leaks but its getting worse, my jeep burned through 2 quarts in 100miles. Here's my dry wet compression test results
dry
1-167
2-125
3-178
4-172
5-170
6-173

wet
1-215
2-172
3-202
4-190
5-190
6-205

cruiser54

　
I'd be looking up ABOVE first, and VERIFYING the source of the oil leak YOURSELF.
Everybody, who doesn't own or have to pay for or perform your vehicle repairs, loves to poke their noggin UNDER the Jeep and come out bearing the false bad news that your RMS is leaking.
Many mechanics, friends, people on Jeep forums who can’t see your Jeep from where they’re at, and good old Uncle Bob seem to enjoy telling you it’s the rear main seal. Has a catastrophic ring to it, doesn’t it?
A simple leak at the back of the valve cover or other source could produce the same symptoms. You don’t need to be a mechanic to figure this out. If you have good eyesight and a dim flashlight, you’re good to go on your own. Don't jump on the RMS/oil pan gasket bandwagon right off the bat.

Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons.
First off, the engine sits nose-up and any oil will run back to the RMS area. Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber's adage apply here. "$hit flows downhill".

Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.
Revised 02-26-2013

Bustedback

The oil control rings on the pistons keep oil from entering the combustion chamber. I had an old Toyota Celica that burned a quart every day because one piston had a broken oil control ring.

884x4

no oil leaks as stated in my last post. its bone dry