How much does a Mercedes C-Class W203 engine replacement cost in the UK?

A reconditioned W203 engine typically costs £1,800–£6,500 supply only, depending on the engine — the volume M271 Kompressor sits at £2,200–£4,000, while the M112 V6 ranges from £3,000–£6,500. Fitting adds £650–£1,500. Use our calculator for a personalised figure.

Which Mercedes W203 engine is the most reliable?

The OM646.962 diesel (C200/C220 CDI, 2003–2007) and the M112 V6 petrol (C240/C320) are the most dependable. The OM646 is an improved common-rail diesel with a proven 200,000-mile-plus lifespan, while the M112 V6 is smooth, robust, and free of major failure modes. The M271 Kompressor is also reliable if the supercharger and chain tensioner are maintained.

What are the common problems with the Mercedes C-Class W203?

M271 supercharger clutch and timing chain tensioner wear, OM611 injector seal failure ('Black Death'), M112 V6 balance shaft wear, and — unrelated to the engine — widespread rust and corrosion on pre-2004 facelift cars.

Is the Mercedes C-Class W203 reliable?

It depends on the engine and the year. Post-2003 facelift cars with OM646 diesels or M112 V6 petrols are genuinely robust. Early cars (2000–2002) with M111 petrols or OM611 diesels are more prone to age-related issues. Rust is the W203's single biggest reliability concern regardless of engine.

Which W203 engine should I avoid?

No engine outright — but the early M111.951/955 (C180, 2000–2002) and OM611.962 (C200/C220 CDI, 2000–2003) are the ones we'd advise caution on. The M111 suffers from camshaft adjuster oil leaks, while the OM611 is prone to injector 'Black Death'. If you buy one, budget for preventative maintenance.

How do I know if my W203 engine needs replacing?

Supercharger clutch rattle or timing chain noise (M271), rough idle or diesel smell (OM611/OM646 injector failure), or balance shaft noise (M112 V6) are key warnings. Use our diagnostic calculator for a personalised assessment.

Is it worth replacing a Mercedes C-Class W203 engine, or should I scrap the car?

Depends on the car's value. Against a well-kept £8,000+ W203 (especially a C320 or low-mileage C220 CDI), a £3,000–£4,500 recon is 38–56% of the car's value — safe. Against a tired £3,000 example with rust issues, a £3,000+ recon may exceed the car's worth — walk away. Our 70% Mercedes threshold is the line.

How long do Mercedes C-Class W203 engines last?

The OM646 diesel and M112 V6 can exceed 200,000 miles with proper servicing. The M271 Kompressor is typically good for 150,000+ miles if the chain and supercharger are maintained. The M111 and OM611 are the shortest-lived due to their known failure modes.

What is the difference between the W203, S203 and CL203?

All three share the second-generation C-Class platform and most engines. The W203 is the 4-door saloon (2000–2006, this page), the S203 is the Estate (2000–2007), and the CL203 is the 3-door SportCoupé (2001–2007). Costs vary slightly by body style due to labour access — see each generation's own page for specifics.

How do I find my Mercedes C-Class W203 engine code?

Listed on the VIN plate and vehicle documentation; the engine code is also stamped on the block. Tell us your variant (e.g., C220 CDI, C180 Kompressor, C320) and registration year, and we'll identify it — 25+ vetted Mercedes specialists will confirm it for free.

W203 Engine Replacement Cost UK

Name: Mercedes C-Class W203 UK Engine Enquiry Data 2025
Creator: MercedesEngines.uk

Mercedes C-Class W203 Engine Codes — The Complete Database

Every engine fitted to the W203 saloon specifically — from the early M111 four-cylinders to the M271 Kompressor units and the V6 petrol and diesel options that arrived with the 2004 facelift.

Engine CodeFamilyFuelDisplacementPowerYears (W203 saloon)Variants (badges)Reliability2025 EnquiriesAvg. Recon Cost

M111.951M111Petrol2.0L129 bhp2000–2002C180★★★☆☆ [PROVISIONAL — see Data Note]— (pattern data)£1,800–£3,200 [MB-QUOTE]

M111.955M111Petrol2.0L129 bhp2000–2002C180 (later)★★★☆☆ [PROVISIONAL — see Data Note]— (pattern data)£1,800–£3,200 [MB-QUOTE]

M271.946M271Petrol, supercharged1.8L143 bhp2002–2007C180 Kompressor★★★★☆ [PROVISIONAL — see Data Note]— (pattern data)£2,200–£4,000 [MB-QUOTE]

M271.940M271Petrol, supercharged1.8L163 bhp2002–2007C200 Kompressor★★★★☆ [PROVISIONAL — see Data Note]— (pattern data)£2,200–£4,000 [MB-QUOTE]

M112.912M112Petrol, V62.6L170 bhp2000–2004C240★★★★☆ [PROVISIONAL — see Data Note]— (pattern data)£3,000–£5,500 [MB-QUOTE]

M112.953M112Petrol, V63.2L218 bhp2000–2005C320★★★★☆ [PROVISIONAL — see Data Note]— (pattern data)£3,500–£6,500 [MB-QUOTE]

OM611.962OM611Diesel2.2L116–143 bhp2000–2003C200 CDI, C220 CDI★★★★☆ [PROVISIONAL — see Data Note]— (pattern data)£2,500–£4,800 [MB-QUOTE]

OM646.962OM646Diesel2.2L102–143 bhp2003–2007C200 CDI, C220 CDI★★★★☆ [PROVISIONAL — see Data Note]— (pattern data)£2,500–£4,800 [MB-QUOTE]

OM612.962OM612Diesel, 5-cyl2.7L170 bhp2001–2005C270 CDI★★★★☆ [PROVISIONAL — see Data Note]— (pattern data)£3,000–£5,500 [MB-QUOTE]

Engine CodeFuelPowerYearsReliabilityEnquiriesAvg. Recon Cost

M111.951M111Petrol129 bhp2000–2002★★★☆☆ [PROVISIONAL — see Data Note]— (pattern data)£1,800–£3,200 [MB-QUOTE]

M111.955M111Petrol129 bhp2000–2002★★★☆☆ [PROVISIONAL — see Data Note]— (pattern data)£1,800–£3,200 [MB-QUOTE]

M271.946M271Petrol, supercharged143 bhp2002–2007★★★★☆ [PROVISIONAL — see Data Note]— (pattern data)£2,200–£4,000 [MB-QUOTE]

M271.940M271Petrol, supercharged163 bhp2002–2007★★★★☆ [PROVISIONAL — see Data Note]— (pattern data)£2,200–£4,000 [MB-QUOTE]

M112.912M112Petrol, V6170 bhp2000–2004★★★★☆ [PROVISIONAL — see Data Note]— (pattern data)£3,000–£5,500 [MB-QUOTE]

M112.953M112Petrol, V6218 bhp2000–2005★★★★☆ [PROVISIONAL — see Data Note]— (pattern data)£3,500–£6,500 [MB-QUOTE]

OM611.962OM611Diesel116–143 bhp2000–2003★★★★☆ [PROVISIONAL — see Data Note]— (pattern data)£2,500–£4,800 [MB-QUOTE]

OM646.962OM646Diesel102–143 bhp2003–2007★★★★☆ [PROVISIONAL — see Data Note]— (pattern data)£2,500–£4,800 [MB-QUOTE]

OM612.962OM612Diesel, 5-cyl170 bhp2001–2005★★★★☆ [PROVISIONAL — see Data Note]— (pattern data)£3,000–£5,500 [MB-QUOTE]

Overview

Mercedes C-Class W203 — Overview

The W203 is the second-generation C-Class, launched in July 2000 as the successor to the W202.

It introduced a stiffer chassis, improved interior quality, and a more modern design language that echoed the larger S-Class. The engine range evolved significantly during production: early cars used the M111 2.0-litre four-cylinder and M112 V6 petrols, with OM611 and OM612 diesels. A major 2002 update replaced the M111 with the M271 Kompressor four-cylinders, while the 2004 facelift brought revised styling, the OM646 diesel, and later the M272 V6 petrols. A 2005 engine overhaul saw the C230K replaced by a V6, the C280 and C350 introduced, and the C320 CDI arriving at the expense of the C270 CDI.

Key Facts

Platform

Mercedes W203 (shared with S203 estate, CL203 SportCoupé)

Predecessor

W202

Successor

W204

Sibling body styles in this generation

S203 Estate, CL203 SportCoupé

Market Intelligence

The W203 C-Class generated 252 real UK engine enquiries in 2025 [MB-VERIFIED], concentrated on the OM611/OM646 diesels and M271 Kompressor petrols as these cars exit affordable-warranty age.

Mercedes C-Class W203 — Overview

The W203 is the second-generation C-Class, launched in July 2000 as the successor to the W202.

It introduced a stiffer chassis, improved interior quality, and a more modern design language that echoed the larger S-Class. The engine range evolved significantly during production: early cars used the M111 2.0-litre four-cylinder and M112 V6 petrols, with OM611 and OM612 diesels. A major 2002 update replaced the M111 with the M271 Kompressor four-cylinders, while the 2004 facelift brought revised styling, the OM646 diesel, and later the M272 V6 petrols. A 2005 engine overhaul saw the C230K replaced by a V6, the C280 and C350 introduced, and the C320 CDI arriving at the expense of the C270 CDI.

Key Facts

Platform

Mercedes W203 (shared with S203 estate, CL203 SportCoupé)

Predecessor

W202

Successor

W204

Sibling body styles in this generation

S203 Estate, CL203 SportCoupé

Market Intelligence

The W203 C-Class generated 252 real UK engine enquiries in 2025 [MB-VERIFIED], concentrated on the OM611/OM646 diesels and M271 Kompressor petrols as these cars exit affordable-warranty age.

Best & Worst Engines

Best Diesel Overall

OM646.962 (C200 CDI/C220 CDI, 2003–2007)

“The OM646 is the improved version of the OM611 — common-rail diesel with better injector reliability, improved emissions, and a proven 200,000-mile-plus lifespan. It's the W203's most dependable diesel, free of the earlier OM611's injector fragility.”

Who it's for: buyers who want a reliable, economical diesel without the V6's complexity.

Best Petrol Overall

M112.953 (C320, 3.2-litre V6)

“The 3.2-litre M112 V6 delivers 218bhp of smooth, naturally aspirated power. No supercharger to worry about, no timing-chain tensioner issues — just a robust, proven V6 that sounds wonderful and keeps going. The C240's 2.6-litre M112 is equally solid.”

Who it's for: buyers who want a smooth six-cylinder petrol without the Kompressor's complexities.

Highest Risk

M111.951/M111.955 (early C180)

“The early 2.0-litre M111 four-cylinder is prone to camshaft adjuster magnet oil leaks that can reach the ECU, plus general age-related oil leaks from gaskets and seals. It's an old engine in an old car — and replacement costs frequently exceed the vehicle's value.”

Who it's for: budget buyers willing to accept age-related issues.

Most Expensive Failure

OM612.962 (C270 CDI, 2.7-litre 5-cyl diesel)

“The five-cylinder OM612 is rare and specialist — when the injectors fail or the turbo goes, parts are harder to find and labour is more intensive than the four-cylinder diesels. Replacement costs can hit five figures on a bad day.”

Who it's for: buyers who need 170bhp diesel torque and are prepared for specialist maintenance.

Best Value

M271.946 (C180 Kompressor, 2002–2007)

“The 1.8-litre supercharged M271 offers 143bhp, decent economy, and the same fundamental robustness as its 163bhp sibling. It's the volume engine for good reason — cheap to run, cheap to replace, and more than enough for UK roads.”

Who it's for: buyers who want a premium badge without the premium running costs.

Most Overlooked

M112.912 (C240, 2.6-litre V6)

“The 2.6-litre M112 V6 is often overlooked in favour of the Kompressor fours or the bigger C320, but it offers 170bhp of smooth, naturally aspirated power without the M271's supercharger complexity. It's the W203's sleeper pick — a petrol that drives like a proper Mercedes.”

Who it's for: buyers who want a V6 without the C320's fuel consumption.

Best Diesel Overall

OM646.962 (C200 CDI/C220 CDI, 2003–2007)

“The OM646 is the improved version of the OM611 — common-rail diesel with better injector reliability, improved emissions, and a proven 200,000-mile-plus lifespan. It's the W203's most dependable diesel, free of the earlier OM611's injector fragility.”

Who it's for: buyers who want a reliable, economical diesel without the V6's complexity.

Best Petrol Overall

M112.953 (C320, 3.2-litre V6)

“The 3.2-litre M112 V6 delivers 218bhp of smooth, naturally aspirated power. No supercharger to worry about, no timing-chain tensioner issues — just a robust, proven V6 that sounds wonderful and keeps going. The C240's 2.6-litre M112 is equally solid.”

Who it's for: buyers who want a smooth six-cylinder petrol without the Kompressor's complexities.

Highest Risk

M111.951/M111.955 (early C180)

“The early 2.0-litre M111 four-cylinder is prone to camshaft adjuster magnet oil leaks that can reach the ECU, plus general age-related oil leaks from gaskets and seals. It's an old engine in an old car — and replacement costs frequently exceed the vehicle's value.”

Who it's for: budget buyers willing to accept age-related issues.

Most Expensive Failure

OM612.962 (C270 CDI, 2.7-litre 5-cyl diesel)

“The five-cylinder OM612 is rare and specialist — when the injectors fail or the turbo goes, parts are harder to find and labour is more intensive than the four-cylinder diesels. Replacement costs can hit five figures on a bad day.”

Who it's for: buyers who need 170bhp diesel torque and are prepared for specialist maintenance.

Best Value

M271.946 (C180 Kompressor, 2002–2007)

“The 1.8-litre supercharged M271 offers 143bhp, decent economy, and the same fundamental robustness as its 163bhp sibling. It's the volume engine for good reason — cheap to run, cheap to replace, and more than enough for UK roads.”

Who it's for: buyers who want a premium badge without the premium running costs.

Most Overlooked

M112.912 (C240, 2.6-litre V6)

“The 2.6-litre M112 V6 is often overlooked in favour of the Kompressor fours or the bigger C320, but it offers 170bhp of smooth, naturally aspirated power without the M271's supercharger complexity. It's the W203's sleeper pick — a petrol that drives like a proper Mercedes.”

Who it's for: buyers who want a V6 without the C320's fuel consumption.

Mercedes C-Class W203 — Ownership Economics

EngineTypical MileageCommon Major FailureRepair Cost (Specialist)Replacement Cost (Recon)Ownership Verdict

M111.951/95580k–120kCamshaft adjuster oil leaks£300–£600£1,800–£3,200

Early Petrol — budget option but ageing.

M271.946/94080k–120kSupercharger clutch, chain tensioner£400–£800£2,200–£4,000

Best Petrol (Value) — reliable Kompressor.

M112.912100k–150kGenerally robust£300–£600£3,000–£5,500

Smooth Six — V6 without the complexity.

M112.953100k–150kGenerally robust£300–£600£3,500–£6,500

Best Petrol — 218bhp V6, no turbo worries.

OM611.96280k–150kInjector fragility£400–£800£2,500–£4,800

Early Diesel — improved by OM646.

OM646.96280k–150kGenerally robust£300–£600£2,500–£4,800

Best Diesel — the W203's most dependable.

OM612.96280k–130kInjector/turbo failure£600–£1,200£3,000–£5,500

Rare Five — specialist territory.

EngineTypical MileageCommon Major FailureRepair Cost (Specialist)Replacement Cost (Recon)Ownership Verdict

M111.951/95580k–120kCamshaft adjuster oil leaks£300–£600£1,800–£3,200

Early Petrol — budget option but ageing.

M271.946/94080k–120kSupercharger clutch, chain tensioner£400–£800£2,200–£4,000

Best Petrol (Value) — reliable Kompressor.

M112.912100k–150kGenerally robust£300–£600£3,000–£5,500

Smooth Six — V6 without the complexity.

M112.953100k–150kGenerally robust£300–£600£3,500–£6,500

Best Petrol — 218bhp V6, no turbo worries.

OM611.96280k–150kInjector fragility£400–£800£2,500–£4,800

Early Diesel — improved by OM646.

OM646.96280k–150kGenerally robust£300–£600£2,500–£4,800

Best Diesel — the W203's most dependable.

OM612.96280k–130kInjector/turbo failure£600–£1,200£3,000–£5,500

Rare Five — specialist territory.

The W203 rule

A £2,500–£4,800 OM646 recon against a £4,000 W203 sits at 63–120% of the car's value. On a sub-£4,000 W203, that brushes our 70% Mercedes threshold — we'll honestly tell you to walk away. Against a well-kept £8,000+ example (particularly a C320 or C270 CDI), the same recon drops to a routine 31–60% — a repair decision, not a financial one. Value the car first.

Common Problems

01

M271

Kompressor Supercharger Clutch & Chain Tensioner

Affected models:

C180 Kompressor, C200 Kompressor (2002–2007).

M271 Kompressor Supercharger Clutch & Chain Tensioner

Typical failure mileage:

60,000–100,000 miles.

Root cause:

The M271's supercharger clutch can fail, causing loss of boost and a rattling noise. The timing chain tensioner is also a known weak point — chain stretch can lead to catastrophic failure if not addressed. Camshaft adjuster magnet oil leaks can reach the ECU.

Tiered Cost Table

Tier

Dealer

Specialist

Scope

Dealer

Specialist

Viability

Our Recommendation

On any W203 Kompressor over 60,000 miles, have the supercharger clutch and chain tensioner checked at every service — £500–£900 now is far cheaper than the £2,200–£4,000+ replacement that follows a skipped chain.

Compare M271 engine prices for your W203 C180/C200 Kompressor

02

OM611

Injector Failure (Black Death)

Affected models:

C200 CDI, C220 CDI (2000–2003, pre-OM646).

Typical failure mileage:

80,000–120,000 miles.

Root cause:

The OM611's injector seals can fail, allowing combustion gases to leak past — this creates carbon buildup (the 'Black Death' effect) and eventually causes injector seizure and cylinder damage. The later OM646 improved this design significantly.

Tiered Cost Table

Tier

Dealer

Specialist

Scope

Dealer

Specialist

Viability

Our Recommendation

At the first sign of rough idle or diesel smell in the cabin, get the injector seals inspected immediately — a £400–£800 repair is dramatically cheaper than the £2,500–£4,800 replacement that follows if ignored.

Compare OM611/OM646 engine prices for your W203 C200/C220 CDI

03

W203

Rust & Corrosion

Affected models:

All W203 variants, particularly pre-2004 facelift cars.

Typical failure mileage:

80,000+ miles.

Root cause:

Not an engine failure, but the W203's most infamous issue — early cars suffer from significant rust on wheel arches, door bottoms, boot lids, and subframes. The 2004 facelift improved rust protection but didn't eliminate it entirely.

Tiered Cost Table

Tier

Dealer

Specialist

Scope

Dealer

Specialist

Viability

Our Recommendation

Have the wheel arches, door bottoms, and subframe inspected on any W203 — rust is the single most common reason an otherwise sound W203 fails an MOT. Pre-2004 cars are most at risk.

Compare W203 rust repair quotes

04

M112

V6 Balance Shaft Wear

Affected models:

C240, C320 (M112 V6 petrols).

Typical failure mileage:

80,000–130,000 miles.

Root cause:

The M112 V6's balance shaft gear can wear, leading to timing issues and engine noise. This is more common on higher-mileage examples and can be expensive to fix.

Tiered Cost Table

Tier

Dealer

Specialist

Scope

Dealer

Specialist

Viability

Our Recommendation

If your M112 V6 develops a rattle or timing noise, get it inspected immediately — £600–£1,000 now is far cheaper than the £3,000+ replacement that follows a complete failure.

Compare M112 engine prices for your W203 C240/C320

W203 Engine Replacement Costs — By Engine and Condition

VariantEngine CodeUsed (Supply)Reconditioned (Supply)Rebuilt (Supply)Labour Hours

C180 (early)M111.951/955£800–£1,500£1,800–£3,200£2,800–£4,5008–12 hrs

C180 KompressorM271.946£1,000–£1,800£2,200–£4,000£3,500–£5,5008–12 hrs

C200 KompressorM271.940£1,000–£1,800£2,200–£4,000£3,500–£5,5008–12 hrs

C240M112.912£1,500–£2,800£3,000–£5,500£4,500–£7,50010–14 hrs

C320M112.953£1,800–£3,200£3,500–£6,500£5,000–£8,50010–14 hrs

C200 CDI (early)OM611.962£1,200–£2,200£2,500–£4,800£4,000–£6,50010–14 hrs

C200/C220 CDI (later)OM646.962£1,200–£2,200£2,500–£4,800£4,000–£6,50010–14 hrs

C270 CDIOM612.962£1,500–£2,800£3,000–£5,500£4,500–£7,50012–16 hrs

No Generation variance from the Model Page's baseline figures — W203 saloon shares identical engine-bay access with its S203 estate and CL203 SportCoupé siblings, so costs are inherited directly per the Authority Model, with no divergence note required.

Core Variants

Diesel Variants

C200 CDIC220 CDIC270 CDI

Petrol Variants

C180C180 KompressorC200 KompressorC240C320

Scope note: All variants listed are W203 saloon only. S203 Estate and CL203 SportCoupé share most of these engines but are covered on their own Generation Pages, since fitment and labour access vary slightly by body style.

Core Variants

Diesel Variants

C200 CDIC220 CDIC270 CDI

Petrol Variants

C180C180 KompressorC200 KompressorC240C320

Scope note: All variants listed are W203 saloon only. S203 Estate and CL203 SportCoupé share most of these engines but are covered on their own Generation Pages, since fitment and labour access vary slightly by body style.

Market Intelligence

Most Requested E90 Engines (2025)

1.1. OM646.962 (C200/C220 CDI) — volume diesel [PATTERN DATA]
2.2. M271.946/940 (C180/C200 Kompressor) — volume petrol [PATTERN DATA]
3.3. M112.953 (C320 V6) — enthusiast favourite [PATTERN DATA]

Most Requested E90 Variants

1.1. C220 CDI
2.2. C180 Kompressor
3.3. C320 [PATTERN DATA]

Average E90 Replacement Cost

£2,200–£5,500 reconditioned, supply only [MB-QUOTE]

Most Common E90 Failures

1.1. M271 supercharger clutch/chain tensioner
2.2. OM611 injector 'Black Death'
3.3. W203 rust/corrosion [PATTERN DATA]

Live Feed

VehicleLocationIssueEnquiries

Mercedes C220 CDI W203 (OM646)

Birmingham

Pre-purchase inspection

5

enquiries

Mercedes C180 Kompressor W203 (M271)

London

Supercharger clutch rattle

4

enquiries

Mercedes C320 W203 (M112)

Manchester

Balance shaft noise

2

enquiries

Updated Monthly

FAQ

BMW 3 Series E90 rear three-quarter view

Why UK Mercedes C-Class W203 Owners Trust MercedesEngines.uk

Trusted W203 Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real W203 owners, as part of the Engine Finders network.
Compare W203 Engine Replacement Companies
see prices, warranty terms and supply & fit options side‑by‑side before you commit.
UK Engine Replacement Services for W203
covering every variant from C180 to C320, with supply‑only or full supply & fit available nationwide.

Find the best Mercedes C-Class W203 engine replacement UK drivers rely on. Compare real prices from trusted specialists on EnginesMarket today and get back on the road with confidence.

Compare Mercedes C-Class W203 Engine Prices on EnginesMarket

Why UK Mercedes C-Class W203 Owners Trust MercedesEngines.uk

Trusted W203 Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real W203 owners, as part of the Engine Finders network.
Compare W203 Engine Replacement Companies
see prices, warranty terms and supply & fit options side‑by‑side before you commit.
UK Engine Replacement Services for W203
covering every variant from C180 to C320, with supply‑only or full supply & fit available nationwide.

Find the best Mercedes C-Class W203 engine replacement UK drivers rely on. Compare real prices from trusted specialists on EnginesMarket today and get back on the road with confidence.

Compare Mercedes C-Class W203 Engine Prices on EnginesMarket

Mercedes C-Class W203 Engines — The Complete UK Guide

Mercedes C-Class W203 Engine Codes — The Complete Database

Mercedes C-Class W203 — Overview

Mercedes C-Class W203 — Overview

Best & Worst Engines

Mercedes C-Class W203 — Ownership Economics

Common Problems

W203 Engine Replacement Costs — By Engine and Condition

Core Variants

Core Variants

Market Intelligence

FAQ

Why UK Mercedes C-Class W203 Owners Trust MercedesEngines.uk

Why UK Mercedes C-Class W203 Owners Trust MercedesEngines.uk