CLS Diesel Engines
from £2,500 to £5,500
Rebuilt units from £3,215 · Common codes: OM642.920, OM642.940, OM651.9xx, OM654.9xx
Mercedes Benz ENGINE MARKETPLACE
Mercedes CLS OM642/M276/M278 Engine Solutions - UK Specialists
Get quotes from trusted UK Mercedes CLS engine specialists. Compare reconditioned & used engines for CLS 220 to CLS 63 AMG - OM642/M276/M278 covered. Get a quote before it's too late.
Supply & Fit Available
12-Month Warranty
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100+ Suppliers
CLS Petrol Engines
from £2,200 to £5,200
Rebuilt units from £2,847 · Common codes: M272.964, M276.920, M278, M256
CLS AMG Engines
from £5,500 to £12,000
Rebuilt units from £6,500 · Common codes: M156.9xx, M157.9xx, M177, M256 EQ Boost
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Supply & fit available - parts and labour from vetted specialistsInstant engine replacement quote - 100% free, no obligationEngine replacement near me - UK-wide specialist networkCompare reconditioned, rebuilt & used engine pricesSupply & fit available - parts and labour from vetted specialistsHow It Works
3 Simple Steps3 Simple Stepsto Finding the Best Mercedes Benz CLS Replacement Engineto Finding the Best Mercedes Benz CLS Replacement Engine
12-Month Warranty
Supply & Fit Available
Nationwide Delivery
Trusted UK Suppliers
Most replacements completed within 3-5 days.
Live UK Engine Market Data
What Are UK Drivers Paying for Mercedes Benz CLS Engine Replacement
The table below shows typical UK rebuilt engine costs across Mercedes Benz CLS variants, covering documented failure causes, chassis generations, engine codes, and fuel types based on current market data.
Average Market Prices
↻ Last updated: 4 Aug 26, 9:26
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Variants We Cover
Mercedes Benz CLS Engine ReplacementAll Variants Covered
Mercedes Benz CLS 400
M276 3.5L Petrol
Rebuilt Engines: £3,800-£6,000
Mercedes Benz CLS Shooting Brake
OM642
Rebuilt Engines: £3,200-£12,000
Not sure which variant your Mercedes Benz CLS is- Enter your registration number above - we'll identify the exact sub-model, engine code and compatible replacement options instantly.
CLS
Engine Codes
Mercedes Benz CLS Engine CodesFull Technical Specifications & Replacement Guide
Every engine code fitted to the Mercedes Benz CLS across three generations (C219, C218, C257), with technical specs, compatible variants and trims, known failure points, and average rebuilt prices from UK specialists. Select any engine code to compare quotes.
Diesel Engines
Extracted from detailed diesel engine families across Mercedes Benz CLS variants.
OM642.920 - 3.0L Diesel
Main replacement triggers are timing chain wear, EGR / cooling faults and turbo-control issues.
Compatible variants
CLS 320 CDICLS 350 CDICLS 350 CDI SportCLS 350 CDI AMG Sport
Avg. rebuilt price
£3,200 - £5,200
Supply only
Technical specifications
- Fuel type
- Diesel
- Engine size
- 3.0L
- Power output
- 224-261 hp
- Years fitted
- 2004-2018
Common failures
- ●Main replacement triggers are timing chain wear, EGR / cooling faults and turbo-control issues.
- ●Confirm exact engine code and fitment before ordering.
- ●Ask for warranty and supply & fit terms.
Not sure which engine code?
Can’t find your engine code- Enter your registration number above - we’ll instantly identify the exact unit, its technical specifications, and live replacement prices from UK Mercedes Benz CLS engine specialists. Every rebuilt engine comes with a minimum 12-month unlimited mileage warranty.
CLS
Common Problems
Mercedes Benz CLS Engine Problems - What It Costs to Fix & When Replacement Makes Sense
Mercedes Benz CLS OM642 Oil Cooler Seal Failure - Why V6 Diesel Engines Leak Coolant Into Oil
Mercedes Benz CLS OM642 Oil Cooler Seal Failure
Most affected vehicles
Mercedes Benz CLS 320 CDI350 CDI
Mercedes Benz CLS 320 CDI, 350 CDI, 350 BlueTEC, 400 CDI (C219 2006-2010, C218 2010-2017, OM642.920 & OM642.940)
Failure mileage range
70,000 - 120,000 miles
Typical failure window
Root cause
The rubber oil cooler seals harden and crack under repeated heat cycles, allowing engine oil and coolant to mix. This creates a mayonnaise-like emulsion, blocks oil passages, and progressively starves the turbo and bearings of clean oil.
Repair options & estimated costs (UK ranges)
| Repair tier | Dealer price | Specialist price | What it involves | Longevity / suitability |
|---|---|---|---|---|
| Preventative - Oil Cooler Seal Replacement | £1,100 - £1,600 | £650 - £950 | Replace oil cooler seals, flush cooling system, change oil and filter | 60,000+ miles when done before contamination damages bearings |
| Intermediate - Turbo & Seal Replacement | £2,500 - £3,800 | £1,600 - £2,400 | Replace oil cooler seals plus turbocharger if oil starvation has damaged bearings | Restores full performance; viable if bottom end is still healthy |
| Full Replacement - Rebuilt Engine | £5,000 - £7,500 | £3,200 - £5,200 (supply & fit) | Supply and fit fully rebuilt OM642 with upgraded Viton seals, new oil cooler, timing components, and bench testing | Factory-spec reliability with upgraded components; 12-month unlimited warranty |
Our recommendation
If caught early (no coolant in oil, no low oil pressure warnings), the preventative seal replacement is excellent value and should be done immediately. Once you see emulsified oil on the dipstick or under the oil cap, the turbo is often already damaged. On a CLS worth £4,000-£8,000, full replacement makes sense if the vehicle is otherwise well-maintained; specialist rebuilds with upgraded seals are considerably cheaper than dealer replacement engines.
Compare rebuilt OM642 engine prices for your Mercedes Benz CLSReplacement Engine Options
Mercedes Benz CLS Engine TypesOptions, Costs & What to Expect
Every engine type is available through our UK network with typical price ranges based on variant, engine code and budget.
Mercedes Benz CLS Reconditioned Engines (Recon)£3,200 - £5,800((supply only))
Mercedes Benz CLS Rebuilt Engines£2,847 - £5,200((supply only))
Mercedes Benz CLS Used Engines£1,800 - £3,500((supply only))
Mercedes Benz CLS Remanufactured Engines£4,500 - £8,500((supply only))
Mercedes Benz CLS Refurbished Engines£2,200 - £3,800((supply only))
Compare Mercedes Benz CLS engine prices with vetted UK suppliers
All engine types include a minimum 12-month unlimited mileage warranty when sourced through EngineMarket. Prices are typical UK market ranges based on historical quote data from our network and depend on exact engine code, variant, mileage and supplier. Use our free comparison tool above - enter your registration to get tailored quotes for your specific Mercedes Benz CLS within hours.
Engine Sizes
Mercedes Benz CLS Engines by SizeFind the Right Displacement for Your Variant
Every displacement fitted to the Mercedes Benz CLS across three generations is listed below, with compatible engine codes, production years and common failure notes.
The 2.1-litre four-cylinder diesel, coded OM651, joined the CLS range with the second-generation C218 model in 2011 as the entry-level diesel option. Badged as the CLS 250 CDI (and later CLS 220 BlueTEC), this engine prioritised fuel economy and lower CO2 emissions over outright performance, making the CLS accessible to a broader audience.
⚙
Engine Code(s)
OM651.924, OM651
▣
Compatible Models (UK)
CLS 250 CDI (C218, 2011-2017), CLS 220 BlueTEC
ϟ
Power output
Verified by registration
△
Common Failure Points
EGR valve failure, swirl flap mechanism failure in intake manifold, injector seal leaks
Production Years: C218, 2014-2017
Get quotes for Mercedes Benz CLS 2.1L diesel enginesMercedes Benz CLS Engines Fuel Type
Mercedes Benz CLS Engines by Fuel Type
Choose your Mercedes Benz CLS engine by fuel type to compare realistic replacement prices, known issues, and compatible UK supply options - from early C219 320 CDI to the latest C257 53 AMG.
Mercedes Benz CLS Diesel Engines
DieselCommon Mercedes Benz CLS Diesel Engine Families
- •OM642.920 - 3.0L V6 (CLS 320 CDI / 350 CDI), oil cooler seal failure at 70k-120k miles
- •OM642.940 - 3.0L twin-turbo V6 (CLS 400 CDI), turbo actuator failure common
- •OM651.924 - 2.1L four-cylinder (CLS 250 CDI / 220 BlueTEC), swirl flap and EGR issues
Found In
- •C219 (2004-2010) - OM642.920 (320 CDI, 350 CDI)
- •C218 (2010-2017) - OM642.920 (350 CDI), OM642.940 (400 CDI), OM651.924 (250 CDI)
- •C218 facelift (2014-2017) - OM642.853 (350 BlueTEC), OM651 (220 BlueTEC)
Known For
- •Strong motorway fuel economy - 45-55 mpg real world
- •OM642 oil cooler seal leaks are the #1 replacement driver
- •OM651 swirl flap failure causing power loss and intake manifold replacement
1 of 3
Mercedes Benz CLS Diesel Engines
DieselCommon Mercedes Benz CLS Diesel Engine Families
- •OM642.920 - 3.0L V6 (CLS 320 CDI / 350 CDI), oil cooler seal failure at 70k-120k miles
- •OM642.940 - 3.0L twin-turbo V6 (CLS 400 CDI), turbo actuator failure common
- •OM651.924 - 2.1L four-cylinder (CLS 250 CDI / 220 BlueTEC), swirl flap and EGR issues
Found In
- •C219 (2004-2010) - OM642.920 (320 CDI, 350 CDI)
- •C218 (2010-2017) - OM642.920 (350 CDI), OM642.940 (400 CDI), OM651.924 (250 CDI)
- •C218 facelift (2014-2017) - OM642.853 (350 BlueTEC), OM651 (220 BlueTEC)
Known For
- •Strong motorway fuel economy - 45-55 mpg real world
- •OM642 oil cooler seal leaks are the #1 replacement driver
- •OM651 swirl flap failure causing power loss and intake manifold replacement
Mercedes Benz CLS Petrol Engines
PetrolCommon Mercedes Benz CLS Petrol Engine Families
- •M272.964 - 3.5L V6 (CLS 350 C219), timing chain tensioner and balance shaft failure
- •M276.950 - 3.5L V6 (CLS 350 C218), direct injection carbon buildup
- •M278.920 - 4.7L twin-turbo V8 (CLS 500), turbo actuator and HPFP failure
Found In
- •C219 (2004-2010) - M272.964 (CLS 350), M156.983 (CLS 63 AMG)
- •C218 (2011-2017) - M276.950 (CLS 350), M278.920 (CLS 500), M157.981 (CLS 63 AMG / 63 S)
- •C257 (2018-present) - M264.920 (2.0L CLS 350), M256.930 (3.0L CLS 450 / 53 AMG)
Known For
- •M272 timing chain rattle on cold start - urgent repair needed
- •M156 head bolt failure can destroy engine without warning
- •M157 offers effortless AMG performance but HPFP failure is common
Mercedes Benz CLS Mild Hybrid (MHEV) Engines
MHEVMercedes Benz CLS MHEV Engine Codes
- •M264.920 - 2.0L four-cylinder (CLS 350), 299hp + 14hp EQ Boost
- •M256.930 - 3.0L inline-six (CLS 450 / CLS 53 AMG), 362-429hp + 21hp EQ Boost
- •48V belt-driven starter-alternator recovers braking energy and assists acceleration
Found In
- •C257 (2018-present) - CLS 350, CLS 450, CLS 450 4MATIC, CLS 53 AMG, CLS 53 AMG 4MATIC+
Important Notes
- •48V battery and electrical system faults are the most common non-engine issues
- •MHEV engine replacement requires hybrid system inspection and software calibration
- •Specialist availability is more limited than non-hybrid CLS engines
Not sure which fuel type your Mercedes Benz CLS has- Enter your registration number above to instantly identify your engine code, fuel system and compatible replacement options - all backed by a minimum 12-month unlimited mileage warranty from UK Mercedes Benz CLS specialists.
Engine YearsGet quotes for 2004-2006 Mercedes Benz CLS replacement engines →
Mercedes Benz CLS Engines by YearWhat Was Fitted & WhenMercedes Benz CLS Engines by Year - What Was Fitted & When
This timeline covers every major engine change across the CLS's three generations - from the pioneering C219 (2004-2010) to the current C257 (2018-present). Use the year blocks below to identify your exact engine and compare rebuilt prices from UK specialists.
⚙Key Changes
- ✓CLS 500 (5.0L V8 M113) and CLS 55 AMG (supercharged 5.4L V8) launch models
- ✓CLS 350 (3.5L V6 M272) joins the range
- ✓CLS 320 CDI (3.0L V6 diesel OM642) arrives 2005
- ✓SBC (Sensotronic Brake Control) system fitted on early cars
▣Main Engines
M272E35 - 3.5L petrol V6 (CLS 350, 268hp)
M113E50 - 5.0L petrol V8 (CLS 500, 302hp)
M113E55 AMG - 5.4L supercharged V8 (CLS 55 AMG, 469hp)
OM642DE30 - 3.0L V6 turbo diesel (CLS 320 CDI, 221hp)
▰Popular Models
- •Mercedes Benz CLS 350
- •Mercedes Benz CLS 500
- •Mercedes Benz CLS 55 AMG
- •Mercedes Benz CLS 320 CDI
🔧Known For
- ✓SBC brake system can be costly to repair when it fails
- ✓M272 V6 timing chain tensioner weakness becomes apparent later
- ✓CLS 55 AMG supercharged V8 offers strong tuning potential
- ✓C219 interior is strictly four-seat layout with no rear bench
Engine Codes Covered:
M272 E35M113 E50M113 E55 AMGOM642 DE30Not sure which year your Mercedes Benz CLS was built- Enter your registration number and we'll identify the exact engine, model year, and compatible replacement options instantly - all backed by a minimum 12-month warranty from UK Mercedes Benz CLS specialists.
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