At the bottom of the base EAC7443 in which sits the oil filler tube in my 1989 3.6 XJ40 there is a drain pipe which goes from the base into the sump. In the engine of the later 4.0 EAC7443 was replaced by EAC2618. EAC2618 has dispensed with the drain pipe. I never thought that the drain pipe was anything other than an unnecessary complication. I would like to dispense with this drain pipe in my 1989 3.6 as I feel it performs no useful function. Any comments would be welcome. See attachments for details.
IMG.pdf (185.3 KB)
IMG_0002.pdf (180.6 KB)
Hi Christopher welcome to the forums. Any car manufacturer that spends money on superfluous items would be rather silly.
If Jaguar deemed that the drain was required they must have had a good reason.
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Hi Robin. I do agree that spending money on superfluous items would be rather silly and this certainly applies to most manufacturers. However it seems Jaguar’s XJ40 project was an exception to the rule. Jaguar made a bypass part (EBC4124) to enable owners to eliminate the superfluous oil cooler. They made a kits to eliminate the self levelling rear suspension. A popular and sensible modification was to convert the brake hydraulic pump system to a more normal vacuum operated system. Later XJ40’s dispensed with the radiator overflow system. The digital dash was changed for a more normal display. Etc etc
In the case that is the subject of my post the oil drain back to sump was eliminated in the later cars.
I am trying to eliminate any unnecessary complication in my car. I know it’s a small thing but eliminating that drain back is just another thing I can do to simplify this car and make it more reliable. Already have vacuum operated brakes, non-self levelling suspension and no oil cooler. Thanks Chris B
Christopher …
On my '89 I have also …
…Installed vacuum operated brakes ,
…Transitioned to traditional non self-leveling rear suspension,
…Removed the oil cooler,
And …
…Removed the “Passive” seat belts and replaced them with conventional 3 point systems, I must admit I did love those weird and quirky attack belts but after several repairs the tracks eventually just wore out.
And don’t get me started on my digital dash, I LOVE THAT THING 
As long as I have a soldering iron and some magnifying glasses it’s staying !
Hi Grooveman
I too love my digital dash. It is spectacular and works perfectly. So does the cruise control.
The seatbelt issue is news to me. My car has what I would call normal seatbelts, but then again I don’t know the history of the car prior to my purchase of it.
Chris
I am not familiar with the XJ40 system, but a word of caution based on my personal experience-
If it is a small diameter hose, it may be there to vent pressure from behind the regulator piston; eliminating it may cause the regulator to lock at full oil pressure. I had this happen to me although for a different reason, I installed a Rover V8 in my MGB with a remote filter adapter. The oil in the filter would drain back from gravity and fill the area behind the regulator piston; the unregulated pressure blew the oil filter off twice before I figured it out.
Leave it as designed would be my advice.