Hi all We're new to this and looking for some advice please. 2007 sprinter 311 cdi lwb, started leaking oil smoke etc. Called green flag, taken to garage who advised the dipstick was loose and oil leaking up through that. Advised to replace dipstick. Ordered new dipstick from mb, doesn't fit, but after talking to people they seem to suggest that the amount of oil coming up through the dipstick means the piston rings have gone. Is this likely and if so what are the options, or could it just be a faulty dipstick or something else. Many thanks in advance for any assistance you can offer.