For an E350 CDI W212/S212, start with the oil-and-filter change and the inspections due, then check when its air filters, cabin filter, fuel filter and brake fluid were last renewed. An advertised A or B service may leave some of those items as additional work. The 231 hp and 265 hp versions also have different fuel-filter catalogue entries.
Coverage: E350 CDI BlueEFFICIENCY W212 saloon / S212 estate, focusing on the 170 kW / 231 hp OM642.850 and 195 kW / 265 hp OM642.852/858 catalogue applications. Later E350 BlueTEC models, petrol E350s and C207/A207 coupés/cabriolets need their own application checks.
E350 CDI service checklist
| Item | What to establish before booking |
|---|---|
| Engine oil and oil filter | The inspected 2012 handbook gives the named E350 CDI an 8.0-litre change reference including the filter. Its DPF-diesel table includes MB 229.51. MANN lists HU 821 x for both covered outputs. |
| Engine air filters | MANN lists C 29 035-2, a pack containing C 29 043 and C 29 044. Check the last replacement record and the complete pack contents. |
| Cabin filter | Compare the activated-carbon CUK 29 005 application with FP 29 005/1, explicitly listed for right-hand drive. |
| Diesel fuel filter | 231 hp OM642.850: WK 820/2 x, with WK 8016 x in the water-sensor-connection branch. 265 hp OM642.852/858: WK 820/14. |
| Brake fluid and coolant | Check dated renewal records and the matching service booklet, rather than relying on a generic service-kit description. |
| Gearbox maintenance | Request the transmission identity, previous oil/filter service record and a separate price for work due. |
| Condition checks | Ask for the inspection findings, distinguishing routine servicing from repairs identified during the visit. |
Use this as a booking and history checklist. Filter fitment tells you what can be fitted; the service schedule and previous work establish what needs replacing now.
What do Service A and Service B mean?
The E-Class handbook describes A as the minor service and B as the major service. Additional characters can indicate additional maintenance work. Send the garage the full reminder, mileage and recent invoices so that it can identify the work and price it accurately.
Our Service A guide and Service B guide explain the labels. The W212 ASSYST PLUS guide provides generation context. A reminder such as B5 is not, by itself, a universal shopping list.
UK service costs: advertised examples
These prices were checked on 24 October 2026:
| Provider and advertised group | Service A | Service B |
|---|---|---|
| Simon Light, Ware: engines over 2400cc; labour, genuine Mercedes parts and VAT included | £250 | £350 |
| MB&B, Cheltenham: E-Class group; VAT included | From £200 | From £330 |
Simon Light describes its figures as basic service prices, with extra prescribed work depending on age and mileage. MB&B also flags possible additional parts or labour. These are published group prices, not individual E350 CDI quotations or a national average.
For a useful comparison, ask each garage to separate the basic service, air/cabin/fuel filters due, brake-fluid work, transmission work and repairs. Confirm the oil product and quantity, VAT and the service-record entry. A lower headline price can cover a different set of operations.
231 hp or 265 hp: why the distinction matters
MANN’s W/S212 catalogue lists the 231 hp OM642.850 application from March 2009 to September 2010, and the 265 hp OM642.852/858 application from August 2010 to December 2015. The dates overlap, so a 2010 registration alone does not select the fuel filter.
The two applications share the listed air-filter pack and oil-filter reference, while the fuel-filter entries differ. Our E350 CDI filter buying guide shows the branches and what to compare on a listing.
Oil, driving pattern and service records
The E350 CDI oil-capacity and approval guide explains the handbook reference and a named Mobil oil option. Agree owner-supplied oil or parts with the workshop before ordering, especially where its service package already includes them.
Mercedes says arduous operating conditions can require more frequent oil, oil-filter and air-filter attention. Tell the workshop about repeated stop-start city use or other demanding operation when discussing the schedule.
Keep an invoice recording oil name and approval, filter references, date, mileage and the work carried out. For a fuel-filter charge, request the fitted reference as well as the general description. That makes the next service easier to plan.
ASSYST PLUS is a service reminder, not an engine-oil-level display. The handbook also notes that battery-disconnected periods are not counted. Record the due date before storage and retain the actual elapsed-time history. Have the reminder confirmed after the required maintenance is completed.
Browse the Mercedes maintenance hub and our Mercedes diagnostic scanner guides for related ownership questions.
Sources
- Mercedes handbook, printed pages 349–350 — ASSYST PLUS, additional work and demanding use; printed pages 441–442 — oil tables and brake-fluid guidance.
- MANN 2024–26 catalogue, printed page 217 / PDF 273 — engine/output branches and filters.
- Simon Light servicing prices and MB&B price guide — dated UK advertised examples and inclusions.
Checked 24 October 2026. The Mercedes-hosted 2012 handbook used here is English-language document 2125847981Z102; its introductory notice specifies German-market applicability. Match its named-model references to the handbook and service information supplied with your car. Parts catalogue dates describe applications, not UK registration cut-offs. Contact Unusual Cars with corrections.
