Passenger side of engine coated in oil
Thread Starter
Junior Member
Joined: Mar 2014
Posts: 57
Likes: 0
From: Sussex County, NJ
Model: Cherokee
Hello everyone this is my first post on here as im looking to get into the jeep world!
Anyway im thinking about buying a 2000 xj with 140,000 miles on it. however i went to check it out yesterday and everything looked good, however the whole left/passenger side of the engine seemed to have a coating of grimy oil on it. it didn't look completely fresh but the look that oil gets when dirt starts to build up on it. it was virtually from the head all the way to the bottom of the block. The owner said hes pretty sure its from continued sloppy filling of oil and it cant be anything leaking from the engine cause all the fluid levels are fine. I guess my big question is. is the a tell tale sign of any common problems with these engines? i know the 2000's tend to have bad heads. any help would be appreciated.
Anyway im thinking about buying a 2000 xj with 140,000 miles on it. however i went to check it out yesterday and everything looked good, however the whole left/passenger side of the engine seemed to have a coating of grimy oil on it. it didn't look completely fresh but the look that oil gets when dirt starts to build up on it. it was virtually from the head all the way to the bottom of the block. The owner said hes pretty sure its from continued sloppy filling of oil and it cant be anything leaking from the engine cause all the fluid levels are fine. I guess my big question is. is the a tell tale sign of any common problems with these engines? i know the 2000's tend to have bad heads. any help would be appreciated.
CF Veteran

Joined: Mar 2010
Posts: 1,442
Likes: 9
From: NC
Year: 99 94
Model: Cherokee (XJ)
Engine: I6
The owner is full of bs. The oil is probably a combination of a leaking valve cover gasket and oil filter adapter o rings.
Both of my 4.0s have that black caked on grime stuff everywhere.
Both of my 4.0s have that black caked on grime stuff everywhere.
CF Veteran
Joined: Dec 2012
Posts: 4,169
Likes: 6
From: York, PA
Year: 1998
Model: Cherokee
Engine: 4.0
Yep, valve cover and OA O-rings. The passenger side of mine is all oil-caked, too. I haven't cared about it enough and haven't seen a drop of oil on the ground or had to add any since my last change. I wouldn't worry too much about it unless it's leaking badly.
CF Veteran
Joined: Jan 2012
Posts: 3,170
Likes: 312
From: Australia
Year: 1997 (RHD)
Model: Cherokee (XJ)
Engine: 4.0 ltr
I think it actually came from factory with the left side coated in oil...then lateron it developes the above leaks to keep it from wearing off.
CF Veteran

Joined: Mar 2010
Posts: 1,442
Likes: 9
From: NC
Year: 99 94
Model: Cherokee (XJ)
Engine: I6
Steady loss of coolant
Milky oil under the oil fill cap
Low compression on cylinders 3 and 4
Last edited by MonacaYankee; Mar 12, 2014 at 12:34 AM.
Trending Topics
change the valve cover gasket and oil filter adapter o-rings...
I just did the valve cover gasket today... super easy.. hardest part was scraping off the sludge from around the head to re-seal the valve cover..
I just did the valve cover gasket today... super easy.. hardest part was scraping off the sludge from around the head to re-seal the valve cover..
CF Veteran
Joined: Apr 2009
Posts: 4,734
Likes: 12
Year: 2015, 2012
Model: Grand Cherokee (WK2)
Engine: 3.6L
As others have said, probably oil filter adapter and/or valve cover gasket.
Grimy oil doesn't hurt the outside of the engine. Helps prevent rust.
If oil is getting on the starter, it can cause it to go out.
BTW, the passenger side of the engine is the right side (on left hand drive vehicles). You call it as to how you sit in the vehicle, not standing in front looking at it.
Grimy oil doesn't hurt the outside of the engine. Helps prevent rust.
If oil is getting on the starter, it can cause it to go out.
BTW, the passenger side of the engine is the right side (on left hand drive vehicles). You call it as to how you sit in the vehicle, not standing in front looking at it.
Last edited by Firestorm500; Mar 12, 2014 at 01:59 AM.
Hey newbie here. Through looking at post and crawling under my jeep I have diagnosed my oil leak to be coming from the oil filter adapter seal/o-ring....bought the o ring from local parts store. How much time should I be looking at to change it?? Any specific tools or helpful hints to make it easier? Heard it is a real pain in the butt. Any information is appreciated.
before anyone flames you... do a search.. there are a ton of write-ups, I know you are new, but this subject has been beaten to death!! Stay with us long enough and you will start to see the common threads...
there are three o-rings to replace, the one that goes around the housing, and two around the bolt... return that kit and get the Mopar P/N 04720363 kit...
read this.. https://www.cherokeeforum.com/f2/oil...g-9625/index4/
I used a L shaped torx bit wrench set from oreillys... and i went from the bottom with a cheater bar on the wrench.. the gear wrench method with popping the bit out of the socket works well too...
there are three o-rings to replace, the one that goes around the housing, and two around the bolt... return that kit and get the Mopar P/N 04720363 kit...
read this.. https://www.cherokeeforum.com/f2/oil...g-9625/index4/
I used a L shaped torx bit wrench set from oreillys... and i went from the bottom with a cheater bar on the wrench.. the gear wrench method with popping the bit out of the socket works well too...
Last edited by JackJare9455; Apr 10, 2014 at 02:33 AM.
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
And use this to diagnose your oil leaks:
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. "$hit flows downhill".
Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.
Revised 02-26-2013
I'd be looking up ABOVE first, and VERIFYING the source of the oil leak YOURSELF.
Everybody, who doesn't own or have to pay for or perform your vehicle repairs, loves to poke their noggin UNDER the Jeep and come out bearing the false bad news that your RMS is leaking.
Many mechanics, friends, people on Jeep forums who can’t see your Jeep from where they’re at, and good old Uncle Bob seem to enjoy telling you it’s the rear main seal. Has a catastrophic ring to it, doesn’t it?
A simple leak at the back of the valve cover or other source could produce the same symptoms. You don’t need to be a mechanic to figure this out. If you have good eyesight and a dim flashlight, you’re good to go on your own. Don't jump on the RMS/oil pan gasket bandwagon right off the bat.
Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons.
First off, the engine sits nose-up and any oil will run back to the RMS area. Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber's adage apply here. "$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
CF Veteran




Joined: Jan 2014
Posts: 1,543
Likes: 351
From: District of Columbia
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
^^^This. I just replaced my valve cover gasket and oil filter adapter O-rings yesterday, so hopefully this'll clear up my similar problem.
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