My daughter has a 2000 MB ML320, which they purchased used with 60k on it. Mobil 1 0w40 is the preferred oil of choice and thats what it got last oil change ( that I paid for). Well it's been 10k miles and it's time for an oil change, that they can't afford and frankly I don't want to fork out the 7-8 bucks a quart for an eight and a half quart sump. I would think a HDEO 5w40 would work? Oil is going to be run 1 year or 10k, mostly city driving. Thoughts and reccomendations please.