It is a relatively easy, but time consuming job in that the oil pan has to
be removed. I had to take one motor mount loose and jack the block a
little. You want to be very careful when putting the new one is so as not
to damage it.

Every time someone mentions replacing the rear main seal here, you get
several comments about the valve cover being your actual problem. Obviously
they have never seen a rear seal leak, but it is as common as the valve
cover in the 4.2 and the 4.0 after say, 80K miles, and very easy to
distinguish the difference.

That said, as they say, its easy to check for a leaking valve cover gasket.

--
JimG
80' CJ-7, 258 CID
35" BFG MT's on 15x10 Centerlines
4.56 D30-D44 SOA
D300 w/4:1 & Currie twin sticks
Warn 8000i w/dual batteries
LockRight F&R


"jbcrow" <jbcrow@flex.com> wrote in message
news:ebd4f35d.0402190152.1cfaa180@posting.google.c om...
> I'm looking to replace the rear crankshaft seal on a 90 XJ 4.0. Anyone
> ever done one of these? It doesn't look too complicated (this is what
> I've said with almost every repair I've ever undertaken!!!). Anything
> in particular to watch for?
>
> TIA
> JB

 

It is a relatively easy, but time consuming job in that the oil pan has to
be removed. I had to take one motor mount loose and jack the block a
little. You want to be very careful when putting the new one is so as not
to damage it.

Every time someone mentions replacing the rear main seal here, you get
several comments about the valve cover being your actual problem. Obviously
they have never seen a rear seal leak, but it is as common as the valve
cover in the 4.2 and the 4.0 after say, 80K miles, and very easy to
distinguish the difference.

That said, as they say, its easy to check for a leaking valve cover gasket.

--
JimG
80' CJ-7, 258 CID
35" BFG MT's on 15x10 Centerlines
4.56 D30-D44 SOA
D300 w/4:1 & Currie twin sticks
Warn 8000i w/dual batteries
LockRight F&R


"jbcrow" <jbcrow@flex.com> wrote in message
news:ebd4f35d.0402190152.1cfaa180@posting.google.c om...
> I'm looking to replace the rear crankshaft seal on a 90 XJ 4.0. Anyone
> ever done one of these? It doesn't look too complicated (this is what
> I've said with almost every repair I've ever undertaken!!!). Anything
> in particular to watch for?
>
> TIA
> JB

 

It is easy to do it with the motor in place. But, you should REALLY take a
look at the Valve Cover Gasket first.




"jbcrow" <jbcrow@flex.com> wrote in message
news:ebd4f35d.0402191029.7754ccb@posting.google.co m...
> jbcrow@flex.com (jbcrow) wrote in message
news:<ebd4f35d.0402190152.1cfaa180@posting.google. com>...
> > I'm looking to replace the rear crankshaft seal on a 90 XJ 4.0. Anyone
> > ever done one of these? It doesn't look too complicated (this is what
> > I've said with almost every repair I've ever undertaken!!!). Anything
> > in particular to watch for?
> >
> > TIA
> > JB
>
> One other note, this is the real oil seal and I plan on doing this
> with the engine in the vehicle. Am I overly optimistic about this not
> being too bad of a job?
>
> thanks again,
> JB

 

It is easy to do it with the motor in place. But, you should REALLY take a
look at the Valve Cover Gasket first.




"jbcrow" <jbcrow@flex.com> wrote in message
news:ebd4f35d.0402191029.7754ccb@posting.google.co m...
> jbcrow@flex.com (jbcrow) wrote in message
news:<ebd4f35d.0402190152.1cfaa180@posting.google. com>...
> > I'm looking to replace the rear crankshaft seal on a 90 XJ 4.0. Anyone
> > ever done one of these? It doesn't look too complicated (this is what
> > I've said with almost every repair I've ever undertaken!!!). Anything
> > in particular to watch for?
> >
> > TIA
> > JB
>
> One other note, this is the real oil seal and I plan on doing this
> with the engine in the vehicle. Am I overly optimistic about this not
> being too bad of a job?
>
> thanks again,
> JB

 

It is easy to do it with the motor in place. But, you should REALLY take a
look at the Valve Cover Gasket first.




"jbcrow" <jbcrow@flex.com> wrote in message
news:ebd4f35d.0402191029.7754ccb@posting.google.co m...
> jbcrow@flex.com (jbcrow) wrote in message
news:<ebd4f35d.0402190152.1cfaa180@posting.google. com>...
> > I'm looking to replace the rear crankshaft seal on a 90 XJ 4.0. Anyone
> > ever done one of these? It doesn't look too complicated (this is what
> > I've said with almost every repair I've ever undertaken!!!). Anything
> > in particular to watch for?
> >
> > TIA
> > JB
>
> One other note, this is the real oil seal and I plan on doing this
> with the engine in the vehicle. Am I overly optimistic about this not
> being too bad of a job?
>
> thanks again,
> JB

 

"JimG" <jimg@cj7_2muchspam.com> wrote in message
news:103c59tjetnlu9d@corp.supernews.com...
> It is a relatively easy, but time consuming job in that the oil pan has to
> be removed. I had to take one motor mount loose and jack the block a
> little. You want to be very careful when putting the new one is so as not
> to damage it.
>
> Every time someone mentions replacing the rear main seal here, you get
> several comments about the valve cover being your actual problem.
Obviously
> they have never seen a rear seal leak, but it is as common as the valve
> cover in the 4.2 and the 4.0 after say, 80K miles, and very easy to
> distinguish the difference.
>

Most of us here that comment that the Valve Cover Gasket is the real problem
replaced the rear main first, and still had an oil leak. Some of us thought
the persistant leak was due to inadvertantly getting the oil pan gasket on
wrong, and aftger fixing that, still had a leak. After parking on a hill and
physically watching the oil flow out of the valve cover was the first clue
that the main seal was not the problem. We are only sharing the experience
in hoping that our brother in Jeeping can benefit from that experience.

In 30+ years of driving and over a dozen cars/trucks, I have never seen a
rear main seal go bad. I understand that I live a particularly protected
life, but the only time I actually considered the rear main seal, my trouble
was the valve cover gasket. Maybe it's just me, but I detect a pattern here.

 

"JimG" <jimg@cj7_2muchspam.com> wrote in message
news:103c59tjetnlu9d@corp.supernews.com...
> It is a relatively easy, but time consuming job in that the oil pan has to
> be removed. I had to take one motor mount loose and jack the block a
> little. You want to be very careful when putting the new one is so as not
> to damage it.
>
> Every time someone mentions replacing the rear main seal here, you get
> several comments about the valve cover being your actual problem.
Obviously
> they have never seen a rear seal leak, but it is as common as the valve
> cover in the 4.2 and the 4.0 after say, 80K miles, and very easy to
> distinguish the difference.
>

Most of us here that comment that the Valve Cover Gasket is the real problem
replaced the rear main first, and still had an oil leak. Some of us thought
the persistant leak was due to inadvertantly getting the oil pan gasket on
wrong, and aftger fixing that, still had a leak. After parking on a hill and
physically watching the oil flow out of the valve cover was the first clue
that the main seal was not the problem. We are only sharing the experience
in hoping that our brother in Jeeping can benefit from that experience.

In 30+ years of driving and over a dozen cars/trucks, I have never seen a
rear main seal go bad. I understand that I live a particularly protected
life, but the only time I actually considered the rear main seal, my trouble
was the valve cover gasket. Maybe it's just me, but I detect a pattern here.

 

"JimG" <jimg@cj7_2muchspam.com> wrote in message
news:103c59tjetnlu9d@corp.supernews.com...
> It is a relatively easy, but time consuming job in that the oil pan has to
> be removed. I had to take one motor mount loose and jack the block a
> little. You want to be very careful when putting the new one is so as not
> to damage it.
>
> Every time someone mentions replacing the rear main seal here, you get
> several comments about the valve cover being your actual problem.
Obviously
> they have never seen a rear seal leak, but it is as common as the valve
> cover in the 4.2 and the 4.0 after say, 80K miles, and very easy to
> distinguish the difference.
>

Most of us here that comment that the Valve Cover Gasket is the real problem
replaced the rear main first, and still had an oil leak. Some of us thought
the persistant leak was due to inadvertantly getting the oil pan gasket on
wrong, and aftger fixing that, still had a leak. After parking on a hill and
physically watching the oil flow out of the valve cover was the first clue
that the main seal was not the problem. We are only sharing the experience
in hoping that our brother in Jeeping can benefit from that experience.

In 30+ years of driving and over a dozen cars/trucks, I have never seen a
rear main seal go bad. I understand that I live a particularly protected
life, but the only time I actually considered the rear main seal, my trouble
was the valve cover gasket. Maybe it's just me, but I detect a pattern here.

 

Hi Jeff,
Ditto, I don't know why we all have jumped to that concussion, the
last time for me on my Bronco it was the oil sending unit, maybe that's
why we've never seen a rear seal leak, we keep replacing them before
they fail.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

CRWLR wrote:
>
> Most of us here that comment that the Valve Cover Gasket is the real problem
> replaced the rear main first, and still had an oil leak. Some of us thought
> the persistant leak was due to inadvertantly getting the oil pan gasket on
> wrong, and aftger fixing that, still had a leak. After parking on a hill and
> physically watching the oil flow out of the valve cover was the first clue
> that the main seal was not the problem. We are only sharing the experience
> in hoping that our brother in Jeeping can benefit from that experience.
>
> In 30+ years of driving and over a dozen cars/trucks, I have never seen a
> rear main seal go bad. I understand that I live a particularly protected
> life, but the only time I actually considered the rear main seal, my trouble
> was the valve cover gasket. Maybe it's just me, but I detect a pattern here.

 

Hi Jeff,
Ditto, I don't know why we all have jumped to that concussion, the
last time for me on my Bronco it was the oil sending unit, maybe that's
why we've never seen a rear seal leak, we keep replacing them before
they fail.
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

CRWLR wrote:
>
> Most of us here that comment that the Valve Cover Gasket is the real problem
> replaced the rear main first, and still had an oil leak. Some of us thought
> the persistant leak was due to inadvertantly getting the oil pan gasket on
> wrong, and aftger fixing that, still had a leak. After parking on a hill and
> physically watching the oil flow out of the valve cover was the first clue
> that the main seal was not the problem. We are only sharing the experience
> in hoping that our brother in Jeeping can benefit from that experience.
>
> In 30+ years of driving and over a dozen cars/trucks, I have never seen a
> rear main seal go bad. I understand that I live a particularly protected
> life, but the only time I actually considered the rear main seal, my trouble
> was the valve cover gasket. Maybe it's just me, but I detect a pattern here.