what size is allen plug on oil pan? also do i need filter wrench for filter removal or is it just a nut,havent really looked under for a while.how many quarts of oil does it take?

I believe it's a 14MM on the drain but it might be a bolt head. The oil filter cartridge should be a 17MM bolt. It's been awhile but I'm thinking it's like 5.6 qts.

If the engine no. OM616.016 oil capacity is 6.5 liters, if 616.012 is 7 liters. If your car equipped with an oil cooler, add half a liter of oil capacity. but when filling oil, don't fill it up to maximum, use the dip stick as your reference the oil should be in the middle bet. the 2 marks. otherwise, the crankshaft seals will leak due to too much oil.