i had castrol magnatec in my car (10w40 semi synthetic) but im not sure what i should actually be using. would a 5w30, 5w40, or 5w50 be best or should i just carry on with the same stuff? will it make a difference to the engine performance and/or longevity of the motor? i have also noticed not many brands do the 5w30.
advice appreciated. cheers.
advice appreciated. cheers.