I searched the forum and this may seem like a daft question but what sort of oil can I use to top up my XJR X308.

I normally just have my car serviced but I need a topup and Ive only covered 4.5k miles since my last oil change

I have lots of 0-40W Fully Synthetic around I use for my Civic Type R, could I use this?

 

Hi
I leave in Constanta Romania near to the sea, in winter we have -15 celsius for a few days, normally we have -5 so for me 5w40 is ok. I do not know how cold is in your area but 5w30 or 5w40 will be very good. I use BMW oil, inside the bottle is Castrol. Jaguar use for this engine Castrol product. Castrol oil in Romania is not so good, i do not know where is made so i buy all the time BMW oil if i want Castrol products. In the past ten years in my last car a BMW i use this oil. So in time this product show me how good it is.

 

Your owner's manual will list all recommended oil viscosities and types, according to ambient temperatures.

 

The standard factory reccomendation is full syn. 5W40
As you are running an XJR with 4.0 litre engine without the VVT units that a normally aspirated 4.0 litre has, you can try the 0W40 in very cold weather but I wouldn't suggest running it in normal temps and definately not in the warmer months....these 0 oils are designed for modern 'eco' engines.
Castrol Edge is the preferred oil and you can go up to 10W50 during the warmer months.
O type oils give rapid drain back into the sump and as most engine wear is caused by cold start up and short trips, it's not a good idea to use them in these engines.
Stick to the factory reccomendations....they did a lot of R&D on this for a reason ;o]

 

Stuck some 5W-40 in her, took just over a litre as well to get to full, she's happy again now.