Quick "fix" for rear main seal leak
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Yes. It's a two piece seal. Some seem to get the pan out pretty easy, for others it's a rel pain fitting it past "stuff".
Likewise the top 1/2 of the seal may go out/in easy, or be a pain.
Then I believe there IS a one piece gasket, not sure we can get them. Some don't get the seal, or the, "sectional" gasket right on the first try. Not having done a 4.0, I'd allow most of a day.
Btw, once I wired on a deflector to keep oil off my pipe. Waz worried it might light on fire!
Likewise the top 1/2 of the seal may go out/in easy, or be a pain.
Then I believe there IS a one piece gasket, not sure we can get them. Some don't get the seal, or the, "sectional" gasket right on the first try. Not having done a 4.0, I'd allow most of a day.
Btw, once I wired on a deflector to keep oil off my pipe. Waz worried it might light on fire!
Last edited by DFlintstone; Jan 24, 2015 at 05:28 PM.
Thread Starter
Senior Member
Joined: Nov 2014
Posts: 603
Likes: 1
From: Hacienda Heights
Year: 1990
Model: Cherokee
Engine: 4.0
Bite me. You're wrong on both statements. If you can replace the rear main in under 10 minutes and without any parts I'll pay you to do it. I'll be generous and pay you a full 1/4Hr. of labor, you stand to make an easy $20.
Thread Starter
Senior Member
Joined: Nov 2014
Posts: 603
Likes: 1
From: Hacienda Heights
Year: 1990
Model: Cherokee
Engine: 4.0
Yes. It's a two piece seal. Some seem to get the pan out pretty easy, for others it's a rel pain fitting it past "stuff".
Likewise the top 1/2 of the seal may go out/in easy, or be a pain.
Then I believe there IS a one piece gasket, not sure we can get them. Some don't get the seal, or the, "sectional" gasket right on the first try. Not having done a 4.0, I'd allow most of a day.
Btw, once I wired on a deflector to keep oil off my pipe. Waz worried it might light on fire!
Likewise the top 1/2 of the seal may go out/in easy, or be a pain.
Then I believe there IS a one piece gasket, not sure we can get them. Some don't get the seal, or the, "sectional" gasket right on the first try. Not having done a 4.0, I'd allow most of a day.
Btw, once I wired on a deflector to keep oil off my pipe. Waz worried it might light on fire!
Thread Starter
Senior Member
Joined: Nov 2014
Posts: 603
Likes: 1
From: Hacienda Heights
Year: 1990
Model: Cherokee
Engine: 4.0
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,578
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
I'm surprised that nobody mentioned this.
I'd do this first if I were you:
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 do this first if I were you:
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
Senior Member
Joined: Nov 2009
Posts: 904
Likes: 3
From: Maine
Year: 1999 Sport
Model: Cherokee
Engine: I6
I think its a good fix. One time I had a leak in my front tire so I bolted and air compressor to the hood, hooked up a long, flexible line to the tire and turned the compressor on low and drove around with it like that, filling the tire as it ran out, no worries.
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
what blows me away is someone was actually proud enough of this "fix" to post it online. el oh el. maybe next you can sand port the head with it still on the jeep, as it requires way too much time for removal..
Senior Member
Joined: Jan 2015
Posts: 641
Likes: 1
From: Anderson, SC
Year: 1999
Model: Cherokee
Engine: 4.0
Come on man, there is a way to have fun without resorting to insults
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
A side story. In my work often I'd need to park places where even a few drops of oil could **** off the client. (like a new, pristine driveway) Sometimes I needed to cary a towel to toss under there, if I wanted to go to work there again tomorrow. (the $ waz worth it!)
Thread Starter
Senior Member
Joined: Nov 2014
Posts: 603
Likes: 1
From: Hacienda Heights
Year: 1990
Model: Cherokee
Engine: 4.0
Thread Starter
Senior Member
Joined: Nov 2014
Posts: 603
Likes: 1
From: Hacienda Heights
Year: 1990
Model: Cherokee
Engine: 4.0
You have a very sad life if insulting a person trying to help other people out makes you feel better about yourself and I want nothing to do with you.
Last edited by cruiser54; Jan 27, 2015 at 02:57 PM.
Thread Starter
Senior Member
Joined: Nov 2014
Posts: 603
Likes: 1
From: Hacienda Heights
Year: 1990
Model: Cherokee
Engine: 4.0
That's more like the IV drip/oil repleneshing system I engineered and am EXTREMELY PROUD of, I'll post photos and details after I've secured the patent.






