Apparently main dealers here in the UK use Castrol semi synthetic 5w-30. Does anyone know which brand/type this is ?
George

 

Castrol is the brand and that is the brand that is recommended in your owners manual.

Semi Syn is in between straight oil and full synthetic. But if you can get or at least have them price Castrol's new Edge full synthetic with a 15,000 mile change interval it is actually less costly than changing your semi syn every 3000 miles. But if you have a high milage, 60,000 plus you may wish to use Castrol GTX for higher milage vehicles. The weight will be the same regardless of the blend. But if you plan on using Castrol you can go to their web site for a complete run down of all the technical stuff. And it could be that your local shop gets a better bulk price on semi syn oil and that is why they are pushing it.

You can also use Mobil 1 products. They have the same range of blends as well.

I can pay $4.50 a quart for semi syn vs $6.90 quart for Syntec vs $8.00 for Edge. Highmilage GTX about the same as semi syn.

 

My 2000 manual doesn't list oil brand names, they only list what weight of oil to use at which outside air temp.

 

Sorry, if my first post was misleading. I was really thinking of Castrol oil names eg Edge, Magnatec or XL. Here in the UK the Magnatec container does not say whether it's semi or synthetic !
I don't want to use fully synthetic as I only do 2/3000 miles a year and of course would be changing oil every year.
My first Jag. and only had it a couple of months. It's a 2003 XK8 4.2 coupe with 88k on the clock and I'm over the moon with it !
Thinking of using Halfords own brand 5w-30. Good or bad Idea ?
Thanks for your replies,
George

 

This link should answer your questions.
http://www.castrolmagnatec.com.au/home/

 

I do use Castrol Edge as well .It's 10W60

 

10W60? where are you driving?

 

Just checked with Sratstone main dealers. They informed that they use Castrol GTX PRO ! It is semi synthetic 5w-30. Must be a special to main dealers.
George