6 Litres.
Funny story here, we own a garage as some of you may now. Anyway, a lady came in via the AA with a C220CDI on a 54 plate.
She had topped the oil up until it came flooding out of the filler cap, it took around 18 litres she said.
If it wasnt for a neighbour of hers seeing this and telling her to get to a garage, she could have been in strife.