awork

My jeep has started leaking.. I'm not sure if it's oil or transmission fluid. The first picture shows where it's dripping from the oil pan and from the bottom of the transmission. I have recently changed t fluid and oil but it started before that. Seems to have got worse after changing the transmission fluid. It's coming from the gap between the engine and transmission. Would that be the rear mail seal or valve cover gasket? Any ideas?

Chuck82

Looks like the rear main seal, they're notorious for leaking, check around your valve cover too see if it's wet around it

DFlintstone

Hardened, leaking O rings in the oil filter adapter will make a leak that blows back and drips right where a RM seal would. Also any restriction in the large vent tube from the valve cover to to air cleaner can cause crankcase pressure, that will make the RM Pee. Stuff to rule out! (besides the valve cover...dizy...oil pressure sender...

awork

I will check all of those tomorrow! It kind of seems like it started a couple months ago around the time I changed the crank position sensor. Is there a possibility that could cause it?

Bobolink

My money's on the oil filter adapter. Got oil on the starter motor, too?

awork

It does seem like there was a little oil on the wires going to the starter

awork

I just went and looked and it's not coming from the oil filter area.

tazunemono

oil filter adapter. Oil drips out the bottom of the flange, out the back of the filter, down on the wires and starter, then into the starter housing and out the bottom of the bell housing.

To diagnose: clean off ALL the old oil drips, then run for 5-10 minutes. Check the oil filter again, and you will see oil on the bottom. Helps if you have a UV light and some dye added. Makes it really obvious where the source is but it has to be fresh.

It's "easy" to fix as it's a $15-20 set of 3 o-rings from the stealer. Actually the filter adapter is kind of a pain to get out, but you can use a T50 tip punched out of a 1/2" socket, a 12mm box wrench, and some zip ties as a makeshift tool. Slide a 3' cheater over and it comes out quick enough.

DFlintstone

Well, that "upside down" guy Roler just beat me to the punch over on an NSS thread, guess I'll jump in with both feet here! awok, like mentioned, you need to watch right away, after blasting it clean at the car wash. Like right there. As soon as the oil blows around, the source is lost...

OIL FILTER ADAPRER O RINGS http://www.myjeepxj.com/cherokee-rep...filter-adapter And... https://www.cherokeeforum.com/f51/oi...o-ring-127359/

Roler

lol.
D, I will always let you have first right of passage, out of respect. You know that, upside or down. Your input is never waisted.
I wasn't aware of any beating to the punches. I respond when I'm online....and sometimes thats other times than you guys

So, please, by all means, be my guest and go first

Trickcomanche

do the rear main and oil pan gasket... Be carefull not to Shave the seal when you install it...It took me 3 times my first time... lol and a lil silicone is your friend too.

awork

Well after further inspection I believe I may have got lucky. It appears the oil is coming from the rear top of the engine. So I believe the valve cover gasket may be the culprit. I am going to change it next week and hopefully that fixes it!

cruiser54

Exactly why I wrote this years ago...............




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

Rockfrog

This, the valve cover and oil filter adapter were leaking enough on my 88 that I suspected a rear main leak.
When I did my driveway re and re the RM was good and sealed. The VC and OFA were my culprits. My leak looked exactly like yours, same oil drip from same spot... They all lead to there.

I can post up the adapter oring sizes ... Making that oring kit $2 just need to know the year. Can't see any signatures on my phone.
87-90 uses a 5/8" hex head bolt on the OFA
91-01 will either be a Allen bolt or a torx bolt (can't remember the changeover year).
Gimme a minute and I'll find the oring sizes.

Rockfrog

some handy info -

Renix era - 87-90

0.799 x 0.103 AS568 size -117
1.296 x 0.139 AS568 size -219
2.484 x 0.139 AS568 size -230

HO era - 91+

0.676 x 0.070 AS568 size -017
0.859 x 0.139 AS568 size -212
2.484 x 0.139 AS568 size -230

the metric filter nipple from Renix era 4.0L's can be swapped for one from a later adapter or from a standard block mount (YJ and TJ) ... part number - 53007563AB.
this will allow the standard later model, common as dog snot, damn near available at the 7-11, PH8A style filter (I use Ford's FL-1A myself).

And here is the picture verification of the Renix sizes for those that need it.
http://s1319.photobucket.com/user/David_Groeneveld/media/Jeep%20Comanche/20140906_104743_zps0jxefpea.jpg.html]

Cost? About $1.92 after taxes Canadian funds and taxation

The HO sizes are currently on my 2000xj ... Just don't have a picture.