Guys,Just was wondering if we are to service according to the service meter when it goes yellow or according to the mileage my mechanic put on the service sticker from the last service?I drive 1991 525i.Maybe the car old so the mechanic put about service every 5,000km. But the service meter really not reach 3 bars yet??!!I takut the workshop take advantage the company account we have there.Which one to trust? Btw, how does the service meter work... milage? impurities of engine oil?