I purchased a 2015 BMW X1 sdrive automatic at 69k at the end of 2021, now it has 80k. After watching Scotty's video I purchased a Bluedrive scanner and it shows my long-term fuel trim at 8%, should I be concerned? If so, what should I do first(besides getting rid of the car..)?
Also, I have another question about what type of engine oil I should use for the next oil change, I live in California. My owner's menu basically said 0w30/5w30/0w40/5w40 will all work in my engine, and during my previous oil change, the mechanic put Castrol 5w40 and some Liqui Moly Molygen additives in it. Since thinner oil creates less friction, should I change to *w-30 this time or should I stick with what I have now?
5w40 is perfect for -10*C to +45*C. 8% is still not bad, if it goes above +15% then you should be worried. Right now it can be a little vacum leak, or bad o2 sensor, or bad ignition parts. Basiclly the ""thicker"" the oil it is best suited for low rpm engines, the ""thinner"" the oil it is best suited for high rpm engines.
The computer is adding fuel, vacuum leaks or an intake manifold gasket leak would be the most common causes. Use the oil specified by the manufacturer without 3rd-party additives.
