Rear Main Seal

[Ben-88Comanche]

So that little oil leak that existed when i bought the truck has slowly become a leak that would probably take a quart a week. Figure its time to change the rear main seal and oil pan gasket, as I already changed the valve cover gasket and I'm pretty positive its the rear main (150k miles).

 

I have read lots of threads about changing it and remember someone said

1- make sure you get mopar seals

 

2-get oil pan gasket for xj 1996+ with the one piece oil pan gasket (not sure of exact year somewhere around 96'

 

anything else I should have in mind? ill probably buy/order the parts this weekend then change it next weekend

Thanks in advance

 

o btw my truck is a 88 4.0 4wd automatic shortbed i think i forgot to put that in

[Motion Offroad]

Also check the oil filter adapter o-ring and gasket. These are also known to leak and are easier (and less expensive) to replace.

 

As far as the gaskets go, yes we've had the best luck with factory Mopar parts.

[mvusse]

Clogged CCV orifice (in valve cover) can cause high internal pressure, causing oil to be forced by the gaskets. If you you replaced the valve cover gasket without cleaning out the CCV orifice, it is quite possible your new valve cover gasket is leaking on the back of the engine.

[KYMJ]

I was planning to go with the 2 lip RM seal from Felpro next week. Anybody used that one?

[Twisty]

Clogged CCV orifice (in valve cover) can cause high internal pressure, causing oil to be forced by the gaskets. If you you replaced the valve cover gasket without cleaning out the CCV orifice, it is quite possible your new valve cover gasket is leaking on the back of the engine.

 

Check the valve cover gasket first!!! I was leaking 1qt/week in my XJ and thought it was the rear main seal. I replaced the valve cover gasket first, and that stopped ALL leaking. It was leaking from the back, and oozing down the back of the engine...fooling me into believing that it was a r/m/s leak. :nuts:

[Pete M]

If you do the RMS, I found it incredibly helpful to squirt grease up into the hold to help installation of the new seal. If you nick or otherwise harm the seal at all, give up and get another. And be careful, but also liberal with the RTV to seal up the corners where the directions say. And let the RTV cure overnight before firing up the engine. It took me 5 tries to get the seal right in my 88. :( Oh, and it's helpful to let the engine sit unmoved for a while before dropping the pan. Lets the oil collect. But be prepared for oil to keep on dripping. Safety goggles and ear plugs are suggested. 8)

[Wildman]

I was planning to go with the 2 lip RM seal from Felpro next week. Anybody used that one?

 

I used the Fel-pro #BS40612 last year with out any problems :brows:

 

The 'one-piece' oil pan gasket is FEL-PRO Part # OS34308R, Much better that the multi piece cork gasket.

 

Motion Offroad, mentioned the oil filter adapter, yes, very good idea to change the O-rings at the same time your doing the pan gasket.

 

Here's an excellent "how-to" that has the correct part numbers for the o-rings, that I didn't follow and bought a "kit" and was missing one of the o-rings, and tossed the rest away :cry:

 

And Pete, why the ear plugs???? It's not a noisy job :roll: Got the rest of the story on that :D Oh, I got it......I love digging rust junk out of the ears :roll:

 

After all this......the only thing left that can leak oil is the Timing cover gasket and seal, but that's a pain, and you need to remove the water pump and Harmonic balancer to get at it :cry:

[Pete M]

I was thinking more along the lines of oil dripping into your ear, but yeah, those of us with rusty and/or dirty trucks can definitely benefit from earplugs. :D It's a good habit when crawling under vehicles.

[MiNi Beast]

If you do the RMS, I found it incredibly helpful to squirt grease up into the hold to help installation of the new seal. If you nick or otherwise harm the seal at all, give up and get another. And be careful, but also liberal with the RTV to seal up the corners where the directions say. And let the RTV cure overnight before firing up the engine. It took me 5 tries to get the seal right in my 88. :( Oh, and it's helpful to let the engine sit unmoved for a while before dropping the pan. Lets the oil collect. But be prepared for oil to keep on dripping. Safety goggles and ear plugs are suggested. 8)

 

:rotfl2: 5 times! :rotfl2:

[jtdesigns]

I was thinking more along the lines of oil dripping into your ear, but yeah, those of us with rusty and/or dirty trucks can definitely benefit from earplugs. :D It's a good habit when crawling under vehicles.

 

Or when your ol lady don't like jeeps and grease!!! lol

[MiNi Beast]

I was thinking more along the lines of oil dripping into your ear, but yeah, those of us with rusty and/or dirty trucks can definitely benefit from earplugs. :D It's a good habit when crawling under vehicles.

 

Or when your ol lady don't like jeeps and grease!!! lol

 

Aww, Jt did your old lady go sucky sucky on your ear and get a taste of 10W 40? :teehee:

[jtdesigns]

I was thinking more along the lines of oil dripping into your ear, but yeah, those of us with rusty and/or dirty trucks can definitely benefit from earplugs. :D It's a good habit when crawling under vehicles.

 

Or when your ol lady don't like jeeps and grease!!! lol

 

Aww, Jt did your old lady go sucky sucky on your ear and get a taste of 10W 40? :teehee:

 

lol,, nah thinking more of her blah,blah,blah,d@mn jeep, blah,blah,, blah... hehe

[MiNi Beast]

I was thinking more along the lines of oil dripping into your ear, but yeah, those of us with rusty and/or dirty trucks can definitely benefit from earplugs. :D It's a good habit when crawling under vehicles.

 

Or when your ol lady don't like jeeps and grease!!! lol

 

Aww, Jt did your old lady go sucky sucky on your ear and get a taste of 10W 40? :teehee:

 

lol,, nah thinking more of her blah,blah,blah,d@mn jeep, blah,blah,, blah... hehe

 

lol

[Wildman]

:rotf:

 

Ahh.......the other reason for wearing ear plugs :yes: