I am a newbie here, and a newbie to solving Jag problems as well. My wife's faithful 88 suddenly pours out (not just drips) oil after engine shutdown. The source is not visible, but appears to originate on the passenger side, hidden from view by what appears to be one of the mufflers. It does not leak, or does so minimally while the engine is running. It appears I would need to remove the heat shield (pretty chrome thingy) to see down behind that muffler to maybe see the source. Does anyone have any experience or clues from this sketchy information?

 

Morning, well here it is anyway. You are NEW, you said that, ha, so WELCOME TO OUR SIDE.

Your '88 is commonly known as an XJ40, confused, so were we at first.

NO harm, some friendly Moderator MAY shift this to the correct area to maximise responses, IF that does not happen, simply repost it in there.

There is not much on the RH side of the AJ6 engine that is oil related.

The camcover gasket is suspect, as are the 2 "D" seals at the rear of cover. Particularly since you are stating it appears to be coming from under the exhaust manifold area??. HOWEVER having said all that, they usually leak more when running, but anything is possible I suppose.

A new camcover gasket, 2 "D" seals, and 6 spark plug tube seals will do NO harm, and just may fix the gremlin.

ENJOY

 

Thank you,
What the hell is an XJ40? Would appear to be at least 34 more than I've got. Anyway, pulled heat shield and could see only a bit more. Oil source still not visible, but would seem to be coming from rear of engine. Cam cover seeping a bit toward rear, but don't know that it could count for the large volume of oil that occurs at shutoff. It wouldn't do it cold, running or stopped, so has to come up to temperature apparently.
Will do the cam cover gaskets etc as they are the only easy things to get at. Maybe I can see something when I get the cover off.

 

OK, the XJ40 is a model identity, as apposed to Series 1/2/3 of this section. Why they NEVER went on with Series 4/5/etc is a mystery that has been discussed forever. the Series 1/2/3 as a 6cylinder (XJ6) ceased in late 1986 (down here at least), but the body shape continued as a V12 engined car until about 1992.

The XJ40 as an XJ6 started in late 1986 (for the 1987 model year MY). It has a single windscreen wiper, as apposed to the 2 on the "Series" cars. Many other differences obviously, but that is a simplistic ID that anyone can usually understand.

My X300 is another model identity, and also has an XJ6 badge on the boot.

The rear of the cylinder head has 2 "D" seals filling half moon openings in the cylinder head that were made when machining the head for the cam bearing journals, and needed to be sealed somehow. Many, many engines have this feature, and use "D" seals the same as the Jag. These "D" seals shrink, and oil finds its way out of the engine.

 

Thank you once again Grant. I induced the leak again by bringing it up to temperature, and again it just pours out below at engine shutoff but not while running. I cannot discern any leakage at the rear cam cover. It seems to originate quite low, rear of engine, near center.

Could this be an oil pan gasket (sump) which leaks as hot oil returns down to the sump at shutoff? I haven't ordered the cam cover gaskets kit, because at least to my amateur eyes the leak is far lower down somewhere.

 

Mmmmmm.

At the rear of the engine is the rear crankshaft seal, and it is encased in its own housing, which would have a "chemical seal" to the engine block.

Rear crank seals are rare for leaking, as is the "chemical seal" for the housing.

These seals "normally" leak whilst running, simply due to oil pressure. So the oil pouring after shutdown is a real mystery to me.

I reckon the only way at the moment would be to get the car up on a hoist, or similar, and run the engine, and observe what is actually going on. I am not aware of any pipes/hoses/etc at the rear of the engine.

The rear seal replacement is NOT a nice job, as the trans needs to come out.

 

Hello Grant,
It may be your very first advice was on the mark. After purchasing an extending mirror, I was able to spot the oil leak, and sure enough it is on the cam cover gasket, very rear, passenger side.
I pulled the cam cover and found the main gasket had shrunk and actually split in half, with a good 1/8 inch gap resulting.
My theory for the mysterious "doesn't leak when running" symptom is that the level of oil was kept high enough on the cams when running, but at shutoff would pool up to the gasket level at this low corner of the cover. Beats me, as it sounds to be a rare phenomenon.
At any rate, I have ordered the gasket kit, including D-Rings and spark plug tube seals, as all seem quite brittle.
Thank you once again, and I will joyously let you know if this cures it.

 

SWEET.

That now gives seriously more drinking time for you and ME. Rear main seals are such a PAIN.

Your theory is very sound, and makes perfect sense to me.

 

Well Grant,
The new gasket did the job! After three days of running around, I now see only a dime-size drip on the floor, and even that may be residual from around the exhaust shields....but who cares? Maybe three drops of oil!
The old cam cover gasket literally fell into pieces on removal. Very brittle after only 25 years. Nothing lasts anymore.