For my XJ40 (AJ6, predecesor to the AJ16), Jaguar recommends various oils for a various ambient temperature ranges.  I am using semi synthetic at the moment, don't remember the viscosity (will have to change the oil after my trip to Paris next week thou  ).  I think I will go for a 10W40 semi synthetic.

I tried synthetic 5W30 in my wifes old Peugeot 405 turbo diesel: the smell is not great, may go for semi-synthetic on the next change!  However, being a turbo diesel and subject to continous cold starts, I have to care about the turbo  , so will stick with a low viscosity oil for that car anyway.

I have never tried all-synthetic in the Jaguar, and at those prices may never give it a go anyway    (is 8 litres, not 4-5!!!) 

Daniel

The problem is your lack of knowledge.
Xj40 engines suffer from condenation in particular (mayonaise) in filler cap. No matter how good a lubricant race spec motul oil is you should not extend the drain intervals because the anti oxidant and anti sludge package in the oil will be exhausted long before it looses its lubrication properties. These contaminents clog up the crank case ventilation system in particular.
Cheers

Why is it every thread including multivalve ends up as a slanging match ? His opinion is as valid as the next mans, although I must admit I don't agree with his tone. Perhaps we should all show a bit of decorum, after all, most of us are polite to each other, and if that doesn't work,
               Brian

Look.
What sort of problem is this?

People seem wedded to some Nostalgia about "my darling Jag must be treated so carefully because it's an old classic".
This is BS.

The one GOOD thing Jaguar did when they put that terrific slant 6 engine was to put a fantastic modern power plant in there that could be driven really hard, and would never go wrong.
The only thing that mystifies me, is why they chose to do away with the oil cooler!
(I always retro fit one, because weather on the continent is hotter).

Jaguar totally failed when they made the V8 that followed it, and engine that has had non stop problems from the outset with premature wear and valve gear that is a total disaster.
I wouldn't own one if you paid me!

I know you may not like my opinions, but a Jaguar is not an idol. It's a car like any other with weaknesses and strengths like any other  (and how!)

You should use modern semi synth or full synth oils in that engine, and it will go on for ever (esp the X300 variant).

I don't know of any modern petrol engine that lasts as long as the X300, so it could be considered as a major unsung success story.

At the end of the day nobody cares because cars are no longer designed to last 20 years.
That was the strength of the Jaguar, Audi and Volvo marques.
Make of it what you like.

http://www.castrol.com/castrol/iframe.do?categoryId=9024084&contentId=7044829
Put you registration number in at the above link and then post what comes up for us all to see.
Cheers

optimus prime wrote on 10.02.2010 at 18:18:26:


It came up with the wrong oil for mine  0W30 it recommends, when Castrol itself make a 5W30 specifically for my engine

Well after a good bit of deliberation and a lot of advice, I've plumped for Redline high performance fully synthetic 10W 40. I'll be flushing out the crankcase filter as well. I'll keep you posted.