Start an E320 CDI W211/S211 service by identifying the engine: this guide covers the 3.0-litre OM642 V6. Match the complete ASSYST message to the service record, choose oil for the fitted DPF equipment, and check the two engine-air-filter positions and fuel-filter connection before buying a kit.
Coverage: E320 CDI V6 W211 saloon and S211 estate with the 2,987 cc OM642.920 engine, 165 kW / 224 hp. MANN catalogues this application from May 2005 to December 2009. These are application dates, not UK registration cut-offs. Earlier OM648 straight-six, petrol E320, BlueTEC and 4MATIC applications are outside this guide.
Which E320 CDI do you own?
| Identification | Covered V6 application | Different earlier application |
|---|---|---|
| Engine | OM642.920 | OM648.961 straight-six |
| Displacement | 2,987 cc | 3,222 cc |
| Catalogue output | 165 kW / 224 hp | 150 kW / 204 hp |
| MANN oil-filter reference | HU 821 x | HU 721/2 x |
The badge alone is insufficient for ordering. MANN records overlapping catalogue ranges during the change between engines, so a 2005 registration is particularly unhelpful as the only identifier. Keep the engine information with the car’s maintenance records.
W211 means saloon and S211 means estate here. The listed OM642.920 engine-filter application covers both. Use body style and fitted equipment separately when selecting suspension, drivetrain or body parts.
What does the ASSYST service letter tell you?
In the inspected 2008 manual, letters A–H describe workshop duration. They do not independently identify a fixed replacement kit. Record the complete display, mileage and date; use the car’s service information and renewal history to establish the operations due.
For wider background, read ASSYST and ASSYST PLUS explained. If searching for “E320 CDI Service C” or a numbered suffix, establish which display and engine the answer covers before applying its checklist.
A practical service-planning checklist
| Item | Useful check before booking or ordering |
|---|---|
| Engine oil | Identify DPF equipment, applicable MB approval and permitted viscosity. |
| Oil filter | Match the OM642 V6 reference rather than the earlier straight-six part. |
| Engine air filters | Account for the left and right positions in the quoted parts. |
| Cabin filtration | Choose a documented right-hand-drive application for a UK RHD car. |
| Diesel fuel filter | Confirm whether a water-sensor connection is required. |
| Brake fluid | The inspected manual specifies renewal every two years; check the dated record. |
These are checks for planning the work, not an instruction to renew every item at every service. A catalogue confirms parts applications; the applicable schedule and previous work determine when replacements are needed.
Compare the operations, then the price
Ask for an itemised quote showing labour, VAT, the oil product and approval, and full part references. Distinguish included engine-air-filter work from cabin-filter work. If only one air-filter item is listed, establish what the supplied package actually contains.
For extra work, record whether it is due under the schedule, proposed because there is no renewal history, or recommended after inspection or diagnosis. This makes a higher quote easier to assess and avoids treating the cheapest headline package as equivalent.
The E320 CDI OM642 oil guide explains the documented replacement quantity and a named oil buying option. Use the V6 filter buying guide to compare complete references before supplying your own parts; agree that arrangement with the workshop first.
Keep gearbox work and faults clearly identified
An engine-service invoice does not document transmission maintenance. If gearbox work is offered, retain its identity, the specified fluid, the operations and the dated invoice separately. This guide does not infer a fluid or renewal interval from the V6 badge.
Report warning lights, reduced power, starting problems or uneven suspension when booking, with the circumstances in which they occur. Routine filter renewal is not proof that a filter caused the complaint. A diagnostic report and an engine service answer different questions.
Store the car’s history as well as its countdown
The manual says battery-disconnected time is not counted by ASSYST PLUS. Note the due date before disconnection, or give the disconnected periods to the workshop. Reset the reminder after the required work and retain the invoice; a fresh countdown is not a list of completed operations.
Find more models in the Mercedes maintenance hub. For a separate fault-reading or tool question, browse our Mercedes diagnostic scanner guides and check the exact diesel vehicle and required function.
Sources and applicability
- Mercedes 2008 E-Class manual, printed pages 243–244 / PDF pages 246–247: service-display meaning and time accounting.
- Mercedes manual, printed page 390: brake-fluid renewal.
- MANN 2024–26 catalogue, printed pages 215–216 / PDF pages 271–272: V6 versus straight-six identities and filter conditions.
Research checked 20 October 2026. The Mercedes-hosted English 2008 manual covers saloon and estate but carries a German-market online disclaimer. Match it to the manual, Service Booklet and supplements supplied with your car; it does not establish every UK build’s complete service schedule.
