[v12-engine] stubborn engine oil leak - car not driven/started in 2 months

V12-Engine
1

Gentlemen:
My XJS 6.0L V12 convertible is taken off-road for the winter
and I am doing some long-overdue maintenance work. As you
can see in my album, the manifolds came out, new everything
in the ‘vee’ – new gortex cam-cover gaskets, upgraded banjo
bolts/washers, spark plugs, etc. I cleaned all the dirt and
grime with lots of towels (and some gasoline for the hard
spots). I also replaced coolant, T-stats, belts, hoses,
etc. (not related to the subject)

This project has taken me all weekends since November 2011.
The engine has not been started in 2+ months, yet, engine
oil keeps dripping at what (to me) seems a fairly
significant rate � a drop a day. The location of the place
where the oil is coming from is just above the oil drain
plug at the rear of the engine, take a look at:

http://www.jag-lovers.org/v.htm?1329074918

It is above the sump pump gasket level and is brown = engine
oil, not ATF. The other side does not have it. Since I am
yet to start the engine, I don’t know if the leak will get
worse with oil pressure from the pump.

I contacted several JL-members off-list and was advised that
the oil pressure switch and the banjo-bolts are prone to
leaks in this area, but I’ve taken care of that and the rear
of the valley is dry and clean.

Where does the oil come from, I am puzzled? I would like to
address it while I am ‘‘there’’. Can anyone point me in a
direction where I should look for the culprit?

Best regards,
Steve–
'95 XJS V12 6.0L, saphire/tan
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2

In reply to a message from sbobev sent Wed 15 Feb 2012:

It might be the rear main seal or the rear main bearing cap seal.
I don’t know if the 6.0 uses the ‘‘hockey sticks’’ but they area a
known trouble spot on the earlier engines. Was it leaking from
here before you parked it for the 2 months? If you’re lucky, the
rear main might seal up afte you run the engine a bit.–
The original message included these comments:

significant rate � a drop a day. The location of the place
where the oil is coming from is just above the oil drain
plug at the rear of the engine, take a look at:
http://www.jag-lovers.org/v.htm?1329074918
It is above the sump pump gasket level and is brown = engine
oil, not ATF. The other side does not have it. Since I am
yet to start the engine, I don’t know if the leak will get
worse with oil pressure from the pump.

–
John Testrake 74XJ12L rhd, 87 XJ12/700R4
St.Louis, United States
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3

In reply to a message from John Testrake sent Thu 16 Feb 2012:

Hi John:
As you can tell from the photos before the work I did, oil
was everywhere. I’ve always had stains in the garage (well
I’ve owned it since 09/2010), but considered the cam-gaskets
and the banjos as the source. Having cleaned the ‘vee’ and
addressed the cam-cover gaskets and the banjo bolts, I did
not expect this to continue.

Is the rear main bearing cap seal visible from down there?
What (if anything) needs to be removed so I can get a visual
and inspect it?

Thanks for your input,
Steve–
The original message included these comments:

In reply to a message from sbobev sent Wed 15 Feb 2012:
It might be the rear main seal or the rear main bearing cap seal.
I don’t know if the 6.0 uses the ‘‘hockey sticks’’ but they area a
known trouble spot on the earlier engines. Was it leaking from
here before you parked it for the 2 months? If you’re lucky, the
rear main might seal up afte you run the engine a bit.

–
'95 XJS V12 6.0L, saphire/tan
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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4

In reply to a message from sbobev sent Thu 16 Feb 2012:

I was going to suggest the rear main when you first posted, but
didn’t want to be such a downer…as it is a major pain to repair.
If the car has not seen regular use, just keep and eye on it, and
maybe it will stop on it’s own. When I first bought my '94 it had
25K mi. on it and no leaks. I promptly changed ALL fluids to
synthetic, and had multiple engine leaks for about a month, then
they magically stopped, and she hasn’t lost a drop since (12 years
now, or more). As to inspecting it, I’m not sure how much you can
see with the flexplate in place…
The 6.0L uses a more modern one piece rubber seal, I think.

Dave
Atlanta 1994 XJS 6.0L–
Penfold99
Atlanta, GA, United States
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5

In reply to a message from Penfold99 sent Sat 18 Feb 2012:

Dave:
I am ready to crank the engine, probably next weekend, but I
am puzzled. If the rear main is above the sump level, and if
the engine is not spinning, why would oil be coming from
there?
Also, I am not sure what the actual geometry is, but if the
rear main is in central location, why would the oil show up at
the right side only?
I will report back what I find out when the car sees more
regular use in the upcoming weeks.
Steve–
The original message included these comments:

I was going to suggest the rear main when you first posted, but
didn’t want to be such a downer…as it is a major pain to repair.
If the car has not seen regular use, just keep and eye on it, and
maybe it will stop on it’s own. When I first bought my '94 it had
25K mi. on it and no leaks. I promptly changed ALL fluids to
synthetic, and had multiple engine leaks for about a month, then
they magically stopped, and she hasn’t lost a drop since (12 years
now, or more). As to inspecting it, I’m not sure how much you can
see with the flexplate in place…
The 6.0L uses a more modern one piece rubber seal, I think.
Dave

–
'95 XJS V12 6.0L, saphire/tan
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6

In reply to a message from sbobev sent Sat 18 Feb 2012:

Well, here is the report I promised – engine was awaken
yesterday for the first time in 3 months. I wiped of the
area before I did the test. This morning I checked – same
story – the RH side shows signs of seepage, while the LH
side is still clean. Not sure if longer engine run would
‘‘cure’’ anything (presuming it is the rear main as suggested
previously). Next project - sump gasket, although I am not
certain this is the culprit.
Regards,
Steve–
The original message included these comments:

I am ready to crank the engine, probably next weekend, but I
am puzzled. If the rear main is above the sump level, and if
the engine is not spinning, why would oil be coming from
there?
Also, I am not sure what the actual geometry is, but if the
rear main is in central location, why would the oil show up at
the right side only?
I will report back what I find out when the car sees more
regular use in the upcoming weeks.

–
'95 XJS V12 6.0L, saphire/tan
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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7

In reply to a message from sbobev sent Sun 26 Feb 2012:

Steve, that’s a strange one. My thought is one of the sandwich
plate bolts is leaking where it exits the top of the plate. I
don’t know why it would continue to leak long after the car is
stored, though. Have you pulled the cover to see if you can track
it to inside or outside of the bell housing?–
John. '95 XJS 6.0L convertible. Southlake, TX
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8

In reply to a message from CJ95 sent Wed 11 Mar 2015:

John:
See here:

This is exactly what I have, Dave’s post confirms it is not
the pan, but the sandwich plate.

You replaced it as part of the timing chain tensioner job,
otherwise, I would have expected that your car will develop
it as well.

Steve–
The original message included these comments:

Steve, that’s a strange one. My thought is one of the sandwich
plate bolts is leaking where it exits the top of the plate. I
don’t know why it would continue to leak long after the car is
stored, though. Have you pulled the cover to see if you can track
it to inside or outside of the bell housing?

–
'95 XJS convertible - V12 6.0L
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