1. M21 Diesel Air Filter (part number 13721285934) (German Purolator AF-3390) - 1 available (2289) - If you own a North American 1985 model year 524td, you'll need to verify which filter is used based on production date (driver's side door jamb).
- If your production date is between early 1984 and 12/1984, you need THIS part # 13721285934 (362 x 259 x 42mm).
- If your production date is between 01/1985 and 12/1985 (representing late-1985 or 1986 model years), you need to order part # 13721287480 (355 x 245 x 50mm).
2. This filter is also suitable for use with a 1986-1988 BMW M5 & M6 (S38B35 engine)
- 1988 BMW M5 (E28 Generation): The AF-3390 is a direct factory cross-reference fitment for the legendary 3.5L S38 inline-six engine. Purolator was actually one of the original component suppliers to BMW for this airbox layout.
Purolator Filters - If you have an old German car that originally called for a Purolator Germany part number, you can still buy the same level of engineering, just in a different box. The legacy catalog numbers and exact factory specifications from Purolator Germany's old European lineup were rolled directly into MANN-FILTER or MAHLE.
