MANN lists HU 721/2 x oil filters for the E320 CDI W211/S211 OM648.961 straight-six. Engine air filters split at chassis A 196439/A 196440: C 12 178/1 before the boundary and C 12 178 after it. Check steering side, climate equipment and fuel-filter connections before completing a kit.
Coverage: E320 CDI W211 saloon and S211 estate with the 3,222 cc OM648.961 straight-six, catalogued at 150 kW / 204 hp. MANN lists November 2002 to June 2005 as its application range, not UK registration cut-offs. The OM642 V6, petrol E320, W210 and other OM648 installations are outside this guide.
OM648 service-filter references
| Item | Reference | Condition |
|---|---|---|
| Engine oil filter | HU 721/2 x | Exact OM648.961 application |
| Earlier engine air filter | C 12 178/1 | Up to chassis A 196439; catalogue to December 2002 |
| Later engine air filter | C 12 178 | From chassis A 196440; catalogue from January 2003 |
| RHD biofunctional cabin option | FP 3172/1 | Confirm actual climate arrangement and any additional filters |
| Diesel fuel filter | WK 820/1 | Match vehicle equipment and connections |
| Optional fuel-filter variant | WK 842/23 x | With water-sensor connection |
These are manufacturer application references. They are not a universal service checklist, renewal interval or guarantee that every part in a retailer’s kit is suitable.
Air filter: the chassis boundary matters
MANN’s current C 12 178/1 page lists the OM648 E320 CDI up to A 196439. Its C 12 178 page lists the same engine from A 196440. The printed catalogue corroborates the two branches.
Match the actual chassis information rather than deciding from first registration. If the identifier or the fitted housing does not correspond clearly to the listed branch, have the supplier resolve the application before ordering. Do not replace an A-prefix condition with a guessed date for a different chassis sequence.
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Up to A 196439 only: Search Amazon for MANN C 12 178/1 air filters
From A 196440 only: Search Amazon for MANN C 12 178 air filters
Keep the full reference, including /1 where specified. These searches can return other parts; confirm the individual result and seller’s application statement.
Oil filter: different from the V6
MANN’s current HU 721/2 x page names E320 CDI W/S211, OM648.961, 3,222 cc and 150 kW. The later V6’s HU 821 x is a different catalogue reference, despite sharing the E320 CDI badge.
For eBay browsing, select the exact car and then verify HU 721/2 x on the individual listing. Confirm the supplied seals and complete package rather than relying on the picture.
The graphic is an affiliate category link, not a pre-filtered compatibility guarantee. The OM648 oil guide covers the separate oil-approval and quantity decisions.
Cabin filters: RHD and early THERMOTRONIC
MANN’s current FP 3172/1 page explicitly lists this E320 CDI engine with a right-hand-drive condition. It is a biofunctional cabin-filter option. The printed range separately lists FP 3172 for left-hand drive; retain the /1 suffix for the documented RHD choice.
Search Amazon for MANN FP 3172/1 cabin filtersEarly climate equipment adds another check. The printed W/S211 table includes CU 18 000-2 and an additional CUK 18 000-2 branch for THERMOTRONIC, with a July 2004 limit and chassis limits A635991 / X170336.
Do not assume one FP 3172/1 purchase accounts for every filter in that early arrangement. Match the climate system and chassis, and have the supplier identify the complete required combination. A shared W211 cabin-filter headline does not establish the same fitting arrangement.
Fuel filter: resolve the sensor connection
The exact engine row lists WK 820/1 and an optional WK 842/23 x branch with a water-sensor connection. Current MANN listings retain that equipment distinction.
Have the actual arrangement confirmed before purchasing. The two references are not offered here as freely interchangeable choices, and the number of filters in a kit does not resolve the connection. Keep the confirmed full reference with the invoice.
Fitment and renewal timing are separate
Use applicable service information and dated renewal records to decide which items are due. Catalogue dates describe the covered application, not when to replace the filter. Our OM648 maintenance guide helps organise that record and compare itemised quotes.
Browse the Mercedes maintenance hub and Mercedes diagnostic scanner guides. For a tool purchase, confirm the exact diesel engine, controller and required function.
Manufacturer evidence
- MANN 2024–26 catalogue, printed page 215 / PDF page 271: full chassis and equipment branches.
- MANN C 12 178/1 and C 12 178: exact chassis boundary.
- MANN HU 721/2 x and FP 3172/1: exact engine and RHD applications.
- MANN WK 820/1 and WK 842/23 x: fuel-filter applications and sensor condition.
Research checked 20 October 2026. Match the actual engine, chassis and equipment before purchase.
