Oil leak RH engine side

Hello everybody,

after several weeks of rest I took the Jag out for an extended ride (50 mls motorway return trip in one day). The good thing: despite less than friendly conditions everything worked as it is supposed to - car started after several weeks of sitting at first turn, all electrical systems including rear heated window, wipers all speeds and return worked in foggy and wet weather - and the car didn’t miss a beat on the early morning ride to the airport and back at night.

Yet, the cat left a puddle of oil at one point at the rh engine side and short behind the front wheel. What is more - when backing out of the garage a track of oil was spilled in a straight line over like 7 feet, indicating that a bigger quantity of oil had accumulated at some point and poured down when the car was set into motion - and it was the second time it did so after a longer period of sitting.

The engine side looks dry from above. The problem is I’d have to leave the car on a lift for several weeks to simulate the situation and be able to check. Whenever I have used the car and taken it to a lift the engine looks, well, Jaguar-like, meaning a bit oily, but nothing indicating a serious leak. My suspicion would be the oil filter (old school paper filter in cartridge).

Are there any other known suspects around this area - external oil lines maybe where gaskets may have hardened out?

Any idea welcome! Enjoy the weekend ahead


75 XJ6L 4.2 auto (UK spec)

Hello Jochen,
Probably wrong engine and gearbox, but I had similar oil leak problems from my GM400 gearbox and V12 engine on a series 3.
The membrane on the vacuum modulator of the gearbox gave up and the gearbox oil went up the hose to the inlet manifold of the air intake of the engine. The oil then leaked out of the air filter box (right side of engine) and down to the floor.

I‘m going to assume that it is neither transmission- nor power steering fluid, both of which would be red (the transmission tends to drip after about three weeks). If it is motor oil, it should be from a non-pressurized part of the engine as it leaks out over time, not because of pressure. First idea is the pressure relief from the filter housing into the oil pan. You could clean it all with brake cleaner and then inspect the hose and gasket there.
Glad the rest works. Do you happen to be in constance on Tuesday or Wednesday?
Have a nice weekend,


Thanks Neil and David!

Strange things can happen, Neil, but in this case - David is right - the oil was quite clearly engine oil, not gearbox oil.

I’ll have to have a closer look at the oil filter connections, I guess - have to find out where that oil pool is forming. Thanks again for the helpful ideas!

Yes David, I’ll be around on Tuesday and Wednesday. PM me to arrange for a meeting.

Enjoy the weekend


75 XJ6L 4.2 auto (UK spec)

It could be from the distributer seal?


Or the dipstick, but neither see that much oil…
Only the return hose sees high pressure after a cold start, and a lot of oil will be bled back to the sump, enough to produce a pint of oil, or more, on cold starts.
Another possibility one might think of is the oil pooling on the front axle, coming from one of the usual leaks and accumulating there just as my size 10 sockets tend to.


I had a similar issue with a leaking oil pressure sender unit on a XK engine. Even with the engine switched off some residue drained from the sender can for a while and dripped from parts already coated in oil.
Of course with the engine off the leak will subside and when the engine is run it can take a while to start leaking.

As I recall, vaguely, there are a lot of seals and stuff around there. some already mentioned. My vote would be for the oil pressure senders…