The Castrol 10w-60 you speak of was made exclusively for BMW M models. I use that along with Redline 10w-60 in my wife's M Roadster. I would stick with the straight 60w synthetic others have mentioned. The Castrol TWS is marketed in the US and is only found at BMW dealers and some BMW performance shops. The Castrol you mentioned is made for European and I guess middle eastern markets.

 

I think you would be fine with a 60wt synthetic or even a 50wt would do. You could also consider extending your change interval if using full syn-- to say 4000 miles easily depending on traffic conditions but your call of course..

if you can't locate a straight weight synthetic then I would consider a 25wt-60 minimum.

good luck and stay 'cool'!

 

Given the environment, I would recommend using the scavenger oil change method. Roguechopper.com

 

That 10w60 oil should be fine or a straight 60 wt but i would shorten my intervals because of the sandy and dusty conditions....maybe around 3500-4000 miles

 

10w doesn't mean 10 degree start ups. That's absurd. The w means winter. 10 means the oil behaves as a 10 grade in winter conditions.
Op a 10w-60 will shear very quickly. I suggest a straight 60 grade for you in the desert. In your operating conditions you want a larger first number and large second number such as a 20w-60 for example.
What can you get ahold of out there. A straight grade would be better. It won't shear at all which means it will stay the same viscosity.
A 10w-60 starts it's life as a 10 grade oil,then viscosity improvers are added to stop it thinning to a 10 grade when hot. These viscosity improvers look like a snake coiled up. As the oil heats up the coils uncoil helping the oil thin less. Over time the coils get cut,it's called shear. So once the coils are cut it will thin more when hot until it thins out to a 10 grade hot.
A straight grade starts life as that particular grade and doesn't shear,maintaining it's film strength.
A multi grade oil is ideally suited for a climate where start up is colder,so the oil pumps faster and heats up to operating temp quicker. Your climate is better suited for a straight grade.

 

Thanks guys for the repalys
But what oil brand have the 60w straight grade. I haven't seen one before

 

I believe amsoil has a straight 60

 

I found the Redline but it's 164$ for 1Q. Is that true


I know this been asked 1000000 time but sorry
What shall I use for the primary & transmition
I found 75w 140, 75w 90 & 80w140 gear oil all are synth oil
& I read in some threads that the synth oil is not recommended in primary is that true

 

$164 is for a box of 12

Red Line 12604 20W-60 Heavy Duty Synthetic Oil - 1 Quart, (Pack of 12)

Last oil change I went with this:
http://www.redlineoil.com/product.aspx?pid=106&pcid=13

 

Amsoil makes a straight 60w

http://www.amsoil.com/storefront/mcs.aspx