1997 jaguar xk8 correct engine oil ?

[charlie boy]

hi guys, I'm a little confused about which is the correct engine oil to use in my 1997 xk8.

jaguar recommended 10/40 semi but every independent jaguar specialist seems to go for 5/30 semi

they say that 10/40 is too heavy for the engine and would take a long time to get to working temperature.

the car has no history of what oil has been used and its done 109,600 miles.

I don't intend to cover large mileage in the car and hope some of you can recommend which type to safely use

[Old Peter]

Hi Charlie,

I wonder if 5/30 semi synthetic was available 18b years ago?

I use 5/30 as recommended by Jaguar on my 2007 plate s type.

Peter.

[charlie boy]

hi peter, I doubt 5/30 was around when my xk8 was manufactured but as we all know as with time progress

goes on. ive spoken to several independent jaguar specialists who say that 10/40 is too thick for the engine though its what jaguar recommend 

and 5/30 semi would be better , ill use there choice as long as theres no detriment to the engine that my main querry .