Hi Folks,

Jasmine, my 96 XJS 4.0 just turned over 100,000. In my driveway, which was neat.

She seems to run just fine, but I noticed that at idle, while driving stop and go, the oil pressure drops way down, just about to 0. It seems fine at other speeds. There is no warning light and the oil is full and clean.

Could this be real, or is it just a sensor / gauge problem?

Thanks,

-mB

 

Normal.

There is an "update" idiot style sender unit that shows normal gauge pressure as long as there is some pressure above a preset point, about 15psi from memory.

 

My 1990 does the same thing, no problem.

 

JLM20791

It's an easy fix.

You may need a crowsfoot to get the old one off. I was able to get it off using a stubby wrench. I forgot what deep socket you'll need to install the new one. I believe its a 19mm, which I didn't have, so I ordered one in advance and it made replacing it a snap.

 

Very common issue with the sending unit on the AJ16. Mine started doing this at 58K miles. My understanding is there is a updated sending unit available that will correct this issue as has been stated already. I just stopped worrying about the reading at warm idle knowing it was a faulty sending unit and after 12K miles of driving no problem.

I am replacing the faulty upper timing chain tensioner this month ( bleeds down when engine is shut off causing a few second rattle from upper timing chain on cold and even warm start up ). I will post the outcome after job is completed just waiting for the gasket. Got a great price on EBAY for a Jaguar factory revised tensioner.

 

Big thank you to all who replied. One less thing to worry about in the short term. In the longer term I'll fix it. Phew.

-mB

 

Looking forward to your feedback. I have a similar short duration squawk on cold start up but haven't got round to doing anything - just coax oil pressure up gently on cold start up. You might find the attached helpful if not seen before.


Cheers,
LeeP

 

Replaced both my 95 XJR and my 96 XJS with new sender, just felt better at stop signs.
Snowball

 

+1 on faulty oil pressure readings - nature of the beast.
As far as the timing chain tensioners per the TSB I had these replaced on my 96 XJS last year and it took care of about 90% of the rattle - still rattles a bit when accelerating on a random basis even when warm but nothing on cold start up.