Rear main seal leak
06-27-2016 | 05:14 PM
#2
CF Veteran
Joined: Oct 2013
Posts: 5,920
Likes: 190
From: Greenville, SC
Year: 1999
Model: Cherokee(XJ)
Engine: 4.0
That's a real bad idea. It'll clog up everything else too. All the little oil passages. I'm sure if cruiser sees this he'll post his look above not below thing. Rarely ever the rear main when people say it is.
06-27-2016 | 09:49 PM
#3
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 19
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
There are O rings in the oil filter adapter that harden and leak, almost always. It then blows back and drips off the bell housing mimicking a RM seal leak. So watch for that! And agreed, don't pour any "stop leak" in it, bad idea.
You should fill out your info so we know what you have, here is cruisers page mostly for Renix Jeeps, has a thing on oil leaks. http://cruiser54.com
You should fill out your info so we know what you have, here is cruisers page mostly for Renix Jeeps, has a thing on oil leaks. http://cruiser54.com
Last edited by DFlintstone; 06-27-2016 at 09:52 PM.
06-27-2016 | 10:02 PM
#4
Junior Member
Joined: Jun 2016
Posts: 78
Likes: 1
From: Chicago
Year: 97 SE
Model: Cherokee
Engine: 4.0L
The only stop leak I would pour in your crankcase is AT-205 Re-Seal. That's about it. That's about the only one I have seen work and has great reviews. Bunch of mechanics use it and go by it, my jeep was only driven 10k miles over a 6 year period, I was leaking some oil when I bought it, after I drove it around some more and finally got warm new oil onto the gaskets and used some AT-205, all the oil leaks stopped. Seals and gaskets can dry up and de-expand after awhile of sitting and not getting proper use, after you put good miles of good clean oil that is heated up on them + a polymer like AT-205, the seals sort of come back to life.
Last edited by jaydubz; 06-27-2016 at 10:04 PM.
06-28-2016 | 09:18 AM
#5
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,566
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
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. "$hit flows downhill".
Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.
Revised 02-26-2013
Everybody, who doesn't own or have to pay for or perform your vehicle repairs, loves to poke their noggin UNDER the Jeep and come out bearing the false bad news that your RMS is leaking.
Many mechanics, friends, people on Jeep forums who can’t see your Jeep from where they’re at, and good old Uncle Bob seem to enjoy telling you it’s the rear main seal. Has a catastrophic ring to it, doesn’t it?
A simple leak at the back of the valve cover or other source could produce the same symptoms. You don’t need to be a mechanic to figure this out. If you have good eyesight and a dim flashlight, you’re good to go on your own. Don't jump on the RMS/oil pan gasket bandwagon right off the bat.
Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons.
First off, the engine sits nose-up and any oil will run back to the RMS area. Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber's adage apply here. "$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
06-28-2016 | 10:18 AM
#6
CF Veteran
Joined: Oct 2013
Posts: 5,920
Likes: 190
From: Greenville, SC
Year: 1999
Model: Cherokee(XJ)
Engine: 4.0
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
06-28-2016 | 10:39 AM
#7
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,566
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
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06-28-2016 | 08:52 PM
#8
CF Veteran
Joined: Oct 2013
Posts: 5,920
Likes: 190
From: Greenville, SC
Year: 1999
Model: Cherokee(XJ)
Engine: 4.0
07-01-2016 | 09:51 AM
#11
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,566
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
07-01-2016 | 02:22 PM
#12
Member
Joined: Apr 2016
Posts: 205
Likes: 1
From: New York
Year: 2000
Model: Cherokee
Engine: 4.0L Straight 6
I thought I had a rear main seal leak so I bought some uv dye to check and I turns out I have the rear mail seal and the oil filter adapter leak. I'd avoid the dealership for the o-rings though, they cost $23.... It's a rip off
07-01-2016 | 02:26 PM
#13
Seasoned Member
Joined: Nov 2014
Posts: 433
Likes: 0
From: Isanti Minnesota
Year: 1994
Model: Cherokee
Engine: 4.0 I6
I just replaced the rear main on my Jeep as well, and it's leaking significantly less than before. Still a little bit but no puddles. Oil filter adapter is probably next.
07-01-2016 | 05:50 PM
#14
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,566
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Do the oil filter adapter first. Wait and see.
07-02-2016 | 10:22 AM
#15
Member
Joined: Jul 2012
Posts: 139
Likes: 0
From: LaGrange Il
Year: 1994
Model: Cherokee
Engine: 4.0
i poured lucas stop leak and a bunch of gear oil in my motor probably 3 years ago now.
my rear main doesnt leak a drop and to my suprise it still runs after all the abuse ive given her!
my rear main doesnt leak a drop and to my suprise it still runs after all the abuse ive given her!