what oil should i choose for my E34 M20B20?
i think to switch to either ARAL or CASTROL.what do you guys recomend for me.The viscosity recomended by the manual is 10w-40 or 15w-40/50.
what oil is better for my engine,does one of the two brands leave sludge in the engine?
i ve also heard that a semisynthetic oil lubricate better than an mineral oil
thanks all!