It is leaking oil from underneath. closer to the middle. Since the day I got it, I guess. (I normally put old card boxes under the car. But eventually I would like to stop the leak.)

Last weekend I raised the front and went under to try to understand where the oil is dripping from.

It appears to me it is coming from the back of the oil pan. Most oil pan bolts along perimiter have oil drops on them, but it is more obvious at the back. See the picture. (The big oil recovery bolt is fine, by the way. It is dry.)

So, what is most likely source of the leak at the back end of the oil pan? Is it a blown oil pan gasket? Or something else?

If it is the oil pan gasket, how easy it is to replace it? Just unbolt everything along perimeter and the oil pan will drop. correct?

 

Replacing the pan gasket is a cake walk. As you say, remove bolts, drop pan, clean surfaces, reinstall. However, the pan bolts to a sandwich plate...which also has a gasket and it a lot more involved to replace

https://www.jaguarclassicparts.com/u...sump-5-3-litre

Sometimes a thorough cleaning followed by re-inspection in a day or two help pinpoint the leak ....or leaks. It's common to have several smaller leaks.

Lacking anything conclusive it couldn't hurt to just replace the pan gasket ...since it's an easy job....and go from there.

Cheers
DD

 

Lots of things it could be. Leaking rear main seal, or the oil pressure sender is on top of the engine at the rear and it and the pressure switch can leak.

 

The fact the pan is almost the lowest point, and as Doug has mentioned, any upper oil leak MUST flow via this area.

The oil drain back pipe and its STUPID 2 small hoses, from the oil filter housing TO the top face of the Sandwich plate is a common leakage area. NOT easy to replace, and LHD makes it a FUN task, NOT. Cannot be seen, it is a "feel" task at best.

The D Seals at the rear of each tappet block leak regularly. Feel around the rear of each tappet block for oil on your fingers. COLD engine, unless you are real game.

The oil switches have been mentioned, and easy enough to do.

Distributor o/ring, it leaks, oil runs to the rear, and down the back, and off the pan bolts.

Rear main seal, NAH. They weep, for sure, but engine 100% dismantled to replace them, and they still weep.

 

Always check the upper oil areas first. Not only can the sender, idiot light, and banjo cause this, so could there two head banjos and the stupid one on the left have side.

Basically, jack your car up and give it a good clean to and bottom. After looking as best you can just clean it all off and start the trace over. Airflow and gravity can move a leak a lot. A pressure sender leak will smoke of on the cats

 

I have a theory on weeping seals, as in rear crank shaft seals. A weep is is a part of the design. To make sure the seal and bearing are lubricated.


Carl

 

As a matter of fact, I do feel/smell/see oil smoking off the cats after long drives. Sometimes more, sometimess less. Occasionally, I can see white smoke would come out from the area of the rear wheels when I stop at a traffic light. (People in cars around me probably think my car is about to explode . I looked under and saw oil on the cats.)

So, the oil on the cats is a sign of oil pressure sender spraying oil in the back?

 

Yes,
A leaking, and only very slightly leaking OP sender blew out about 60% of my engine oil over a 300 mile journey. Oil all over the underside of the car, etc etc. Almost impossible to detect at tickover. As my v was relatively clean, leaning over the sender with a flashlight (torch) when I rev'd the engine I could just see a drop of clean oil coming out of the sender.
Either that or the cam cover gaskets and half moon seals are the most likely culprits. Also, the tappet block join, which is not gasketed, is a likely oil source. If you ever get in there, inlet manifold off, do the lot. The tappet block join is not under pressure, just gravity, so it can be sealed with high temp RTV from outside, after careful cleaning and a bit of roughing up the surface. Daim did a great smart job on his, this attached pic is my less expert effort. But it does work.
Greg

 

I guess I will have to take it slow, step by step, working from top down. (In the meantime, adding half-quart of oil every other week is not a big deal for me.)

Today I tried looking hard for suspiciously oily areas starting from the top. What I found is that Block B (LHS) is definitely more oily comparing to Block A. Also, the oiliness increases moving toward the back of the block. It is not like I see a puddle of oil. No. Just oily areas around gasket and around. Especially towards the B5 and B6.

I tried to take pictures, but the space is very tight and I did not want to risk dropping my iPhone in there Pictures are of both front and the back around B6 cylinder


Looks like camshaft/tappet block gasket on B side might be shot.

How easy/difficult is it to replace camshaft gasket? Possible w/o pulling the engine? Do I have to take everything from the top (fuel rails, manifolds, all hoses/connectors, etc)?

 

Looks normal V12 oil mist gatherung.

A good clean, without flooding the thing, is the only way.

Oily stuff that far forward is heading for distributor o/ring, and they do leak badly eventually.

Check the bolts that secure the plate in the centre of the "V", as they could be loose, and a that will allow oil splash to escape. NOT stupid tight, they will snap and ruin your week.

As Greg mentioned, the tappet block to head leak is "usually" noticed more on the outside area, due to the angle of the dangle, and gravity.

 

Doing the cam cover gaskets and half moon seals does not need the engine removed. You remove the intake manifolds, as a unit complete with the injector rail, two people can do it quite easily. Then the cam covers just undo and a good clean, paint and new gaskets (must be OEM gortex ones) and new half moon seals will do it.
As Grant suggested, CAREFULLY cleaning the V out is important while you are in there, AND properly sealing the intake holes in the head AS SOON as you have removed the manifolds! White spirit and a metal toothbrush, kitchen paper, horrible job but worth it afterwards.
Also you can check the siring in the V, check the injector loom etc etc. From your pics it looks like the cam cover gaskets are shot, and while you are in there, renew the senders anyway.
Greg