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90 Wrangler YJ needs Rear Main Seal

Ok,

I'm hoping to get some quick advice on replacing the rear main seal in
my 90 wrangler. I've got the 258 - 4.2L engine with manual
transmission. I've been trying to determine where my oil leak is and
have determined with some help that its the Rear Main Seal leaking.
How hard is it to replace this? And I know looking up the part for
it, it asks if its the 1 piece or 2 piece seal which if I'm looking at
things right I think with the setup I have its the 1 piece seal. Can
anyone verify that for me and let me know what type of nightmare it is
going to be to replace that?

Thanks.

Re: 90 Wrangler YJ needs Rear Main Seal

First thing you will hear from most others in this group is that your
problem is more likely the valve cover gasket. (Maybe you have already heard
it)

Mine (80 CJ) was a 2 piece seal... not that hard to replace. You must
remove the oil pan. The passenger side motor mount on my CJ had to be
removed.

--
JimG
80' CJ-7 258 CID, HEI
4.56 Gears, Lock-Right F&R
35" BFG MT on 15x10 Centerlines
D44 Rear, D30 Front. SOA
Dana 300 w/4:1 & Currie twin sticks
Warn X8000i w/ dual batteries

00' TJ Sport 4.0L, 5sp
4.56 Gears, TrueTrac rear
33" BFG AT on 15x8 Eagle Alloys
D35 Rear, D30 Front. 3" Suspension Lift
Warn X8000i

"NewbieJeepGuy" wrote in message...
> Ok,
>
> I'm hoping to get some quick advice on replacing the rear main seal in
> my 90 wrangler. I've got the 258 - 4.2L engine with manual
> transmission. I've been trying to determine where my oil leak is and
> have determined with some help that its the Rear Main Seal leaking.
> How hard is it to replace this? And I know looking up the part for
> it, it asks if its the 1 piece or 2 piece seal which if I'm looking at
> things right I think with the setup I have its the 1 piece seal. Can
> anyone verify that for me and let me know what type of nightmare it is
> going to be to replace that?
>
> Thanks.
>

Re: 90 Wrangler YJ needs Rear Main Seal

JimG said it:
FWIW, I found the bolts for the valve cover on my '89 YJ 4.2
finger tight. Torqued them and my rear main seal leak was gone.
Joe

"JimG" <JimG@nospam.com> wrote in message
news:drsvh.1538$B25.1416@news01.roc.ny...
> First thing you will hear from most others in this group is that your
> problem is more likely the valve cover gasket. (Maybe you have already
heard
> it)
>
> Mine (80 CJ) was a 2 piece seal... not that hard to replace. You must
> remove the oil pan. The passenger side motor mount on my CJ had to be
> removed.
>
> --
> JimG
> 80' CJ-7 258 CID, HEI
> 4.56 Gears, Lock-Right F&R
> 35" BFG MT on 15x10 Centerlines
> D44 Rear, D30 Front. SOA
> Dana 300 w/4:1 & Currie twin sticks
> Warn X8000i w/ dual batteries
>
> 00' TJ Sport 4.0L, 5sp
> 4.56 Gears, TrueTrac rear
> 33" BFG AT on 15x8 Eagle Alloys
> D35 Rear, D30 Front. 3" Suspension Lift
> Warn X8000i
>
> "NewbieJeepGuy" wrote in message...
> > Ok,
> >
> > I'm hoping to get some quick advice on replacing the rear main seal in
> > my 90 wrangler. I've got the 258 - 4.2L engine with manual
> > transmission. I've been trying to determine where my oil leak is and
> > have determined with some help that its the Rear Main Seal leaking.
> > How hard is it to replace this? And I know looking up the part for
> > it, it asks if its the 1 piece or 2 piece seal which if I'm looking at
> > things right I think with the setup I have its the 1 piece seal. Can
> > anyone verify that for me and let me know what type of nightmare it is
> > going to be to replace that?
> >
> > Thanks.
> >
>
>

Re: 90 Wrangler YJ needs Rear Main Seal

I've done this 3 or 4 times, the folks at AutoZone kept giving me the
double-lip seal and it kept leaking. My '88 has a single-lip 2-piece
seal, though visually I simply can't tell the difference between the
double and single lip versions (other than the color of the rubber).
You're looking for Fel-Pro gasket part # BS13879 (I'm almost positive,
if it's not that it's something close.) The biggest trouble you'll
have is reinstalling the top half - the instructions say to use liquid
soap to lube it up, but I ended up putting a coat of lithium grease on
the thing, then dunking it in the motor oil I'd drained out of the
pan. Use a screwdriver to compress the side of the top seal as you
push it in with your fingers to keep from shredding the outside of it
on the block.. If you've never done this before it's good to have a
backup seal just in case you do shred it. Take your time and wear eye
protection, oil will drip off your crankshaft and into your eyes. The
lower half of the seal just Other than that it's a very
straightforward operation, all you have to do is unbolt your starter
(I just let the thing hang on a piece of rope so I wouldn't have to
undo all the wiring to it) and then undo 20 or 30 7/16" bolts around
the oil pan to get at the thing.

The obligatory Jeep group statement on leaking 258's: Check Your
Valve Cover Gasket. 99% of the time, due partially to the downward
slant of the engine, oil will leak out of the back of your valve
cover, run down the engine, and fall on the ground between engine and
tranny, causing you to believe your RMS is bad. Stuff a rag between
the back of your block and your firewall. If it has oil on it, you've
found a leak. It might not be a bad idea just to replace the VC
gasket first, since the part costs no more than $5 and is simple to
replace. This can also happen with your valve cover (PCV) grommets
getting old and dry - oil can leak out of them and down the back of
your block. That being said, if it *is* your rear main seal, check
your timing chain while you've got the oil pan out. If it moves more
than an inch or so with just your finger, you may as well replace it
while you're in there.

If you run into problems, send me an e-mail. I could probably do a
rear main seal in a 258 blindfolded. Good luck.

On Jan 29, 2:04 pm, "JimG" <J...@nospam.com> wrote:
> First thing you will hear from most others in this group is that your
> problem is more likely the valve cover gasket. (Maybe you have already heard
> it)
>
> Mine (80 CJ) was a 2 piece seal... not that hard to replace. You must
> remove the oil pan. The passenger side motor mount on my CJ had to be
> removed.
>
> --
> JimG
> 80' CJ-7 258 CID, HEI
> 4.56 Gears, Lock-Right F&R
> 35" BFG MT on 15x10 Centerlines
> D44 Rear, D30 Front. SOA
> Dana 300 w/4:1 & Currie twin sticks
> Warn X8000i w/ dual batteries
>
> 00' TJ Sport 4.0L, 5sp
> 4.56 Gears, TrueTrac rear
> 33" BFG AT on 15x8 Eagle Alloys
> D35 Rear, D30 Front. 3" Suspension Lift
> Warn X8000i
>
> "NewbieJeepGuy" wrote in message...
> > Ok,
>
> > I'm hoping to get some quick advice on replacing the rear main seal in
> > my 90 wrangler. I've got the 258 - 4.2L engine with manual
> > transmission. I've been trying to determine where my oil leak is and
> > have determined with some help that its the Rear Main Seal leaking.
> > How hard is it to replace this? And I know looking up the part for
> > it, it asks if its the 1 piece or 2 piece seal which if I'm looking at
> > things right I think with the setup I have its the 1 piece seal. Can
> > anyone verify that for me and let me know what type of nightmare it is
> > going to be to replace that?
>
> > Thanks.