Hi and greetings from the UK.

I'm new to Jaguars and XJS in particular. My recently acquired 1990 XJS, 3.6 (135,000 miles) takes longer than I would expect for the oil pressure to build up. After an overnight stand I am looking at 10 seconds for the oil pressure gauge to start registering and 30 seconds to reach 75 psi. This is all at tick-over as I do not rev the engine until full oil pressure. Engine sounds slightly tappety during the build up but after the initial 30 seconds engine sounds sweet and oil pressure between 45 and 75 psi depending on engine speed.

The pressure build up is quicker if the car is only left to stand for an hour or so.

Recent filter and oil change (semi synthetic 10/40).

What is the norm for these engines? Is there anything I can do to speed up the oil pressure build up. Am I heading for a major rebuild, empty wallet and tears?

Thanks for reading,

LeeP

 

Welcome to the forum.
Empty wallet and tears are normal for XJS ownership and that is without a major rebuild.
If you have a friendly garage get them to fit a remote gauge and take a reading, it could just be the sender that is on the way out.
I don't know about the 3.6 ones but on my 4 litre one I had to change the sender every couple of years.

 

Thanks Steve,


I'm beginning to realise that, like a good mistress, the XJS will probably empty my pockets and then move on to a more affluent owner but it will be fun while it lasts.


I will look into the sender switch but my gut feel from the sound of the engine is that pressure is low on cold start up.


I wonder if the oil is draining out of the oil filter overnight? I had similar problems with MGBs in the past until I found a type of filter with a good non-return valve (Fram). What filters do others use?


LeeP

 

As said above.

The oil filters are basically horizontal mounted, and drain back is REAL. I use Crosslands (Made in UK) when I can find them, no issues.

Our 3.6 XJ40 sometimes took time, and a simple "blipp" of the throttle, sorted it instantly. That car ran 10W40 oil all round round.

Of course, yours could have had lousy service schedules, "El Cheapo" oil used, and the carbon build up inside the engine could be sad. Good quality oil, changed regularly, will eventually flush this out. Some owners use an engine oil flush, your choice here.