Mercedes Benz R Class 280 CDI/320 CDI Engine ReplacementCompare Prices & Get Quotes
Get quotes today from trusted UK Mercedes Benz R Class 280 CDI and 320 CDI engine specialists. Compare prices on reconditioned, rebuilt and used engines for the 3.0-litre OM642 V6 diesel - supply & fit available nationwide.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
From £2,400 to £4,600
Used from £1,500 · Reconditioned from £2,400 · Common codes: OM642.950, OM642.870
From £1,500
Tested, bare/short engine
From £2,400
Rod bearings addressed, tested
From quote
Upgraded bearings, full teardown, revised valvetrain
Secure enquiry - no spam, no pressure. Genuine quotes only from vetted UK Mercedes R Class 280 CDI and 320 CDI specialists.
3 Simple Steps3 Simple Stepsto Finding the Best Mercedes Benz R Class 280 CDI/320 CDI Replacement Engineto Finding the Best Mercedes Benz R Class 280 CDI/320 CDI Replacement Engine
Most replacements completed within 3-5 days.
Variant HistoryMercedes Benz R Class 280 CDI/320 CDI - Engine History & Specs at a Glance
The R 320 CDI launched with the W251 generation in 2006 as the core diesel variant, powered by the OM642 3.0-litre V6 diesel producing 224hp. The R 280 CDI joined the range as the entry-level diesel in September 2006, using the same 3.0-litre V6 turbodiesel engine but electronically restricted to 188bhp. Both variants shared the same 7-speed automatic transmission and permanent 4MATIC all-wheel drive system, with the R 280 available in short-wheelbase form to keep it below the £40,000 mark. Production continued until 2012 for UK models.
Variant HistoryMercedes Benz R Class 280 CDI/320 CDI - Engine History & Specs at a Glance
The R 320 CDI launched with the W251 generation in 2006 as the core diesel variant, powered by the OM642 3.0-litre V6 diesel producing 224hp. The R 280 CDI joined the range as the entry-level diesel in September 2006, using the same 3.0-litre V6 turbodiesel engine but electronically restricted to 188bhp. Both variants shared the same 7-speed automatic transmission and permanent 4MATIC all-wheel drive system, with the R 280 available in short-wheelbase form to keep it below the £40,000 mark. Production continued until 2012 for UK models.
Mercedes Benz R Class 280 CDI/320 CDI
Fuel TypeDiesel (common-rail V6 turbodiesel)
Engine Size3.0L (2,987cc)
Power Output Range188-224hp across the variant's historyEngine History Timeline
OM642.950 3.0L V6 diesel, 224hp @ 3,800rpm (R 320 CDI, W251 launch)
September 2006 - OM642.950 3.0L V6 diesel, 188hp @ 4,000rpm (R 280 CDI, entry-level, electronically restricted)
2009 - R 280 CDI and R 320 CDI available in standard and 4MATIC variants
R 280 CDI replaced by R 300 CDI in facelift range
2012 - R 320 CDI continues as core diesel variant through to end of UK production
Key Specs Snapshot
Fuel TypeDiesel (common-rail V6 turbodiesel)Engine Size3.0L (2,987cc)Power Output Range188-224hp across the variant's historyYears Produced2006-2012 (UK)Every engine fitted to the Mercedes Benz R Class 280 CDI and 320 CDI is covered below, with UK rebuilt pricing and known failure points - from OM642 timing chain stretch to oil cooler seal degradation.
Mercedes Benz R Class 280 CDI/320 CDI Engine Codes - Specifications & Replacement CostMercedes Benz R Class 280 CDI/320 CDI Engine Codes - Specifications & Replacement Cost
3.0L V6 Diesel (2006-2012)
Power Output188 hp (140 kW) @ 4,000 rpm (R 280 CDI); 224 hp (165 kW) @ 3,800 rpm (R 320 CDI)Torque440 Nm (R 280 CDI); 540 Nm (R 320 CDI)Years Fitted2006-2012Displacement2,987ccCylindersV6, 24-valve, DOHCEngine CodeOM642.950
Compatible Trim Levels
- R 280 CDI
- R 280 CDI 4MATIC
- R 320 CDI
- R 320 CDI 4MATIC
- R 320 CDI Sport
Find your exact engine code, specs and UK replacement cost guide.
Used
Tested, ready-to-fit engine
£1,500-£2,800
Reconditioned
Addressed known issues, tested
£2,400-£3,600
Rebuilt
Full teardown, upgraded internals
£2,800-£4,600
Common Failure
Timing chain stretch and guide failure - the rear-mounted tensioner loses hydraulic pressure over time, allowing the timing chain to stretch and plastic guides to wear, typically between 80,000-120,000 miles. Oil cooler seal degradation leading to coolant contamination is also common, along with swirl flap mechanism failure in the intake manifold.
The R 280 CDI and R 320 CDI's OM642 V6 diesel is a fundamentally robust engine, but it has well-documented weaknesses that become more pronounced with age and mileage. The most critical issue is timing chain stretch and guide wear, followed by oil cooler seal degradation and swirl flap failure. Every rebuilt engine supplied through EnginesMarket includes upgraded components addressing these original failure points, plus a minimum 12-month unlimited-mileage warranty.
The R 280/320 CDI's Most Critical Weakness
Affected Vehicles
Mercedes R 280 CDI, R 320 CDI (OM642.950, 2006-2012)
Typical Failure Mileage
80,000-120,000 miles
Root Cause
The rear-mounted timing chain tensioner loses hydraulic pressure over time, allowing the chain to stretch and plastic guides to wear. Cold-start rattling between 900-1,200rpm is the classic warning sign. If ignored, guide fragments can enter the oil sump, causing catastrophic engine failure.
Why It Happens
The rear-mounted timing chain tensioner loses hydraulic pressure over time, allowing the chain to stretch and plastic guides to wear. Cold-start rattling between 900-1,200rpm is the classic warning sign. If ignored, guide fragments can enter the oil sump, causing catastrophic engine failure.
Dealer (parts + labour)
£1,800-£2,800
Specialist (parts + labour)
£1,200-£1,900
What it involves
Full chain tension, guide swap, and updated tensioner fit without engine removal
Suitability
60k-80k miles if caught before rattling escalates
1 - 2 daysDealer (parts + labour)
£4,800-£6,500
Specialist (parts + labour)
£2,800-£4,600
What it involves
Engine removal, bench rebuild with upgraded timing assembly, new seals, supply & fit installation
Suitability
100k+ miles with 12-month unlimited mileage warranty
1 - 2 daysAll prices are indicative UK market ranges based on current UK specialist supplier data.| Repair Tier | Dealer (Parts + Labour) | Specialist (Parts + Labour) | What It Involves | Suitability | Estimated Time |
|---|---|---|---|---|---|
 Intermediate - Timing chain & guide replacement Minor | £1,800-£2,800 | £1,200-£1,900 | Full chain tension, guide swap, and updated tensioner fit without engine removal | 60k-80k miles if caught before rattling escalates | 1 - 2 days |
 Full Replacement - Rebuilt OM642 engine Best Value | £4,800-£6,500 | £2,800-£4,600 | Engine removal, bench rebuild with upgraded timing assembly, new seals, supply & fit installation | 100k+ miles with 12-month unlimited mileage warranty | 1 - 2 days |
Vehicle Value Check
Vehicle Value Check
A typical 2006-2012 R 280 CDI or R 320 CDI is worth approximately £3,000-£8,000 depending on mileage and condition. These large luxury MPVs have suffered significant depreciation, meaning replacement costs can approach or exceed vehicle value. For well-maintained examples with good bodywork and transmission health, replacement remains justifiable.
Our Recommendation
Our Recommendation
If you hear a metallic rattle on cold start between 900-1,200rpm, act immediately. A preventative chain and guide replacement is cost-effective on low-mileage examples. Once plastic guide fragments enter the oil sump or the tensioner fully collapses, a complete OM642 rebuilt engine is the safer, more economical route.
Don't Let Timing Chain Stretch, Oil Cooler Seals, or Swirl Flap Failure Write Off Your Mercedes R 280 CDI or 320 CDI
Whether you're facing OM642 timing chain stretch on your R 320 CDI, oil cooler seal degradation, or swirl flap failure, EnginesMarket makes it simple to compare quotes from trusted UK Mercedes diesel specialists. Every rebuilt engine in our network carries upgraded components addressing the original design weakness - reinforced timing components, Viton oil cooler seals, and updated intake systems - plus a minimum 12-month unlimited mileage warranty with nationwide delivery and supply & fit options. Don't pay main dealer premiums. Compare prices from independent Mercedes specialists who know these OM642 V6 diesels inside out.
Compare rebuilt OM642 Mercedes R 280 CDI/320 CDI engine prices
12-Month Minimum
UK Specialists Vetted
Best Price GuidanceImportant Information
Important Information
"All prices are indicative UK market ranges based on historical quote data and repair requests from our network of engine specialists. Dealer pricing is estimated based on published main dealer labour rates and genuine OEM parts pricing. Specialist pricing reflects actual quote data from EnginesMarket's UK network. Actual costs vary depending on damage severity, vehicle condition, variant, and workshop location within the UK. Use our free comparison tool to get tailored quotes for your specific Mercedes R Class 280 CDI or 320 CDI. Every engine supplied through EnginesMarket carries a minimum 12-month unlimited mileage warranty - always confirm exact terms with your chosen supplier."
Mercedes Benz R Class 280 CDI/320 CDI Engine ReplacementFrequently Asked Questions
Question 1How much does a Mercedes R 280 CDI or 320 CDI engine replacement cost in the UK-
Short summary: A rebuilt OM642 engine for the R 280 CDI or R 320 CDI costs £2,800-£4,600 supply-only. Fitting adds £800-£1,500 depending on complexity - the OM642 V6 requires specialist knowledge for proper installation.
- R 280 CDI / R 320 CDI (OM642.950): rebuilt unit £2,800-£4,600; used engine from £1,500
- OM642 timing chain replacement (labour only): £1,200-£1,900 at specialist
- OM642 oil cooler seal replacement: £950-£1,400 at specialist
Question 2What are the signs of timing chain failure on a Mercedes R 320 CDI-
Short summary: A rattling noise on cold start between 900-1,200rpm is the classic warning sign on the OM642 engine. If ignored, it can lead to engine seizure and catastrophic failure.
- Cold start rattle that disappears after oil pressure builds - earliest warning
- Check engine light with timing correlation codes
- Metallic swarf in engine oil indicates chain guides wearing away
- Preventative chain replacement costs £1,200-£1,900 at specialist
Question 3Is the Mercedes R 280 CDI or 320 CDI engine (OM642) reliable-
Short summary: The OM642 V6 is fundamentally robust, but R Class owners should be aware of timing chain stretch between 80,000-120,000 miles, oil cooler seal degradation, and swirl flap failure. With these addressed, the engine is capable of 150,000+ miles.
- OM642 V6 is fundamentally robust with proven durability
- Timing chain stretch is the most critical failure point
- Oil cooler seal degradation affects many units from 90,000 miles
- Well-maintained OM642 engines exceed 150,000 miles
Question 4How long do Mercedes R 280 CDI and 320 CDI engines last-
Short summary: Properly maintained OM642 engines routinely reach 150,000-200,000 miles before major work is needed. One owner reported 200,000 km (124,000 miles) with the engine still running.
- OM642 (R 280/320 CDI): 150,000-200,000+ miles with regular servicing
- Timing chain inspection recommended from 80,000 miles
- Service interval is 10,000 miles or 12 months - use Mercedes-spec low-SAPS oil (MB 229.51)
- Late oil changes accelerate timing chain wear and oil cooler seal degradation
Question 5Is it worth replacing the engine in my Mercedes R 280 CDI or 320 CDI-
Short summary: Yes, if the R Class is otherwise in good condition with no rust or major transmission faults. A rebuilt OM642 costs £2,800-£4,600 - comparable to the value of a £3,000-£8,000 vehicle, making it a justifiable investment for well-maintained examples.
- R 280/320 CDI values: £3,000-£8,000 depending on year, mileage and condition
- Rebuilt engine with upgraded components fixes original weak points
- Supply & fit typically £3,600-£6,100 depending on engine code
- New engine includes 12-month unlimited mileage warranty
Question 6What oil does my Mercedes R 280 CDI or 320 CDI need-
Short summary: Mercedes-Benz specifies low-SAPS oil meeting MB 229.51 - typically 5W-30. The OM642 V6 requires approximately 8.5 litres with filter.
- OM642 (R 280/320 CDI): MB 229.51 5W-30 low-SAPS - protects DPF and emissions systems
- Never use non-approved oil - can cause timing chain and injector issues
- Change every 10,000 miles or 12 months - stretched intervals cause timing chain wear
Why Choose UsCompare Mercedes R Class 280 CDI/320 CDIEngine PricesToday
500+ OM642 V6 diesel engines supplied through our network
12-Month Warranty on every rebuilt R 280 CDI and 320 CDI engine
Nationwide UK delivery
supply & fit available for OM642
Comparing quotes for your Mercedes R 280 CDI or 320 CDI is completely free, with no obligation and no pressure. Enter your registration above to get tailored quotes from UK Mercedes diesel specialists who understand the OM642 V6 engine inside out. Whether you need a used engine, a reconditioned unit, or a full rebuilt engine with upgraded timing components, oil cooler seals, and swirl flap components, we'll connect you with the right specialist for your exact R Class - with a minimum 12-month warranty on every engine supplied.
Enter your registration
and get matched with verified Mercedes Benz R Class 280 CDI/320 CDI specialists.