Classic Volkswagens mainly have a steel oil filler cap, Beetles, early buses, bay windows with upright engines and so onÂ… but Volkswagens with Type 4 ,engines, wasserboxers and later Diesels have a plastic oil filler cap. Now we have this oil seal for those plastic caps, and it will fit most plastic oil filler caps of the entire VAG group! A very universal product at a hell of a price!