how does the oil grades thing work? & will it be ok to use castrol rs 0w 40 in my motor?

Grabber
have a look here mate Click here

Pete

cheers mate
um is this the real pslewis!!!!!!!!!!!lol

No:rolleyes:

ok, so I can see roughly what 10W30 means...

...but what does it mean specifically.
Does it mean the oil is adequate for a temp range of 10ºF to 300ºF
(which is -12ºC to +149ºC BTW).

Not sure what the operating temp for oil is in an average engine, something over 100ºC though.

Scooby normal OT 70-110 depending on how you drive and the ambient termperature.

NO! it`s too thin. A 5/30 is the minimum. You would be better off with a fully synthetic oil if your engine is well run in and a 10/40 or a 15/50 from the likes of Mobil 1 or Millers 300v competition would suit your engine and give extra protection.
Subaru 2000/1 Rally team used Miller oils. The sae number represents the "thickness" or viscosity of the oil when cold/hot.
Hope this helps.
Bob