which engine oil?
i know this has been talked about alot but i have a 98 328is. i would like to get other opinions on which oil is best. synthetic vs regular oils and the best weight to use for the summer. ive heard that heavier oils will make your engine run more sluggish than the thinner oils. i know that the manufacture prefers we use the heavey oils like 10w40 and up even in the newer models. ive been thinking of trying synthetic 5w30 as synthetic will stand up best. any thoughts would be appreciated. thanks in advance.