I'm amazed at how people concentrate on saving a few bucks on oil when maintenance has so little impact on the cost of ownership.

I use Mobil 1 and change it every six months or 3,700 miles, whichever comes first.

Using OEM filters, it costs me less than $30 for an oil change. I can't even buy my wife lunch for that any more.

It's rediculous to worry about the cost of oil when a new MB engine costs more than my first house.

BTW, a true synthetic will greatly reduce the possibility of gelling/sludge. I would never use the so-called A oil. They will never give you a staight answer about things and make rediculous recommendations and claims.