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

 

Yup, the leak from the valve cover that is pretending to be a rear crank
seal leak....

These engines are tilted back and the valve covers tend to leak. This
runs right down a grove in the back and drips off the bell housing
bottom or oil pan.

To test, run the engine for a bit, then take a clean rag and wipe the
head below the valve cover. If you come up with oil, then I recommend
you change this gasket before worrying about the bottom.

If the bottom does need fixing, the pan comes off fairly easy, the
starter might be in the way.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

jbcrow wrote:
>
> 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

 

Yup, the leak from the valve cover that is pretending to be a rear crank
seal leak....

These engines are tilted back and the valve covers tend to leak. This
runs right down a grove in the back and drips off the bell housing
bottom or oil pan.

To test, run the engine for a bit, then take a clean rag and wipe the
head below the valve cover. If you come up with oil, then I recommend
you change this gasket before worrying about the bottom.

If the bottom does need fixing, the pan comes off fairly easy, the
starter might be in the way.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

jbcrow wrote:
>
> 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

 

Yup, the leak from the valve cover that is pretending to be a rear crank
seal leak....

These engines are tilted back and the valve covers tend to leak. This
runs right down a grove in the back and drips off the bell housing
bottom or oil pan.

To test, run the engine for a bit, then take a clean rag and wipe the
head below the valve cover. If you come up with oil, then I recommend
you change this gasket before worrying about the bottom.

If the bottom does need fixing, the pan comes off fairly easy, the
starter might be in the way.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

jbcrow wrote:
>
> 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

 

Replacing that seal is an easy job, but it is probably not necessary. The
WAY more common ailment that gives a symptom similar to that is the Valve
Cover Gasket. The VCG typically breaks somewhere towards the rear of the
motor, and the oil flows out and down the back of the block, into the bell
housing, and down to the inspection plate that covers the flywheel or torque
converter. It LOOKS for all the world like the rear main has taken a dump,
but it is really the VCG.




"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

 

Replacing that seal is an easy job, but it is probably not necessary. The
WAY more common ailment that gives a symptom similar to that is the Valve
Cover Gasket. The VCG typically breaks somewhere towards the rear of the
motor, and the oil flows out and down the back of the block, into the bell
housing, and down to the inspection plate that covers the flywheel or torque
converter. It LOOKS for all the world like the rear main has taken a dump,
but it is really the VCG.




"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

 

Replacing that seal is an easy job, but it is probably not necessary. The
WAY more common ailment that gives a symptom similar to that is the Valve
Cover Gasket. The VCG typically breaks somewhere towards the rear of the
motor, and the oil flows out and down the back of the block, into the bell
housing, and down to the inspection plate that covers the flywheel or torque
converter. It LOOKS for all the world like the rear main has taken a dump,
but it is really the VCG.




"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

 

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

 

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

 

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