How much does a Mercedes W204 engine replacement cost in the UK?

A reconditioned W204 engine typically costs £1,500–£12,000 supply only [MB‑QUOTE], depending on engine — the four‑cylinder diesel (OM646/OM651) runs £2,500–£5,500, while the M156 V8 in the C 63 AMG can cost £6,000–£12,000. Fitting adds £650–£1,300. Use our calculator for a personalised quote.

Which Mercedes W204 engine is the most reliable?

The OM646 2.1‑litre diesel (pre‑2010 C 200/220 CDI) is the most dependable — it’s simple, robust, and lacks the rear‑mounted timing chain of its OM651 successor. Among petrols, the post‑2011 M276 3.5‑litre V6 is a significant improvement over the balance‑shaft‑prone M272.

What are the common problems with the Mercedes W204?

Pre‑2009 M272 V6 petrols suffer balance‑shaft gear wear; OM651 diesels have a rear‑mounted timing chain that can stretch; OM642 V6 diesels leak oil from the cooler seals; and M156 V8s (C 63) can develop cam lifter wear. Regular servicing is critical across all engines.

Is the Mercedes W204 reliable?

It depends on the engine and year. Pre‑facelift (2007–2010) V6 petrols have a known weakness; post‑2011 petrol V6s are much improved. The OM646 diesel is solid; OM651 needs chain monitoring. Overall, a well‑maintained W204 with a proven engine can be a reliable executive car — but do your homework.

Which Mercedes W204 engine should I avoid?

We don’t recommend a blanket “avoid,” but a pre‑2009 M272 V6 without documented balance‑shaft replacement is a high‑risk purchase. Similarly, an early C 63 AMG (pre‑2010) without cam lifter history should be approached with caution. Always get a specialist pre‑purchase inspection.

How do I know if my W204 engine needs replacing?

Key warning signs include: cold‑start rattle (OM651 chain), a ticking or rattling from the front of the engine (M272 balance shaft), burning oil smell (OM642 seals), or a top‑end tick that worsens (M156 lifters). If you experience any of these, get a diagnosis immediately — early intervention saves thousands.

Is it worth replacing a Mercedes W204 engine, or should I scrap the car?

Depends on the car's value. Against a well‑kept £8,000 W204, a £3,000 OM651 recon is 37% of the car's value — safe if the car is otherwise sound. Against a tired £4,000 example, the same recon is 75% — brushing our 70% Mercedes threshold, so evaluate scrap. Use our 70% rule as your guide.

How long do Mercedes W204 engines last?

With proper maintenance, the OM646 diesel can exceed 250,000 miles, and the M276 V6 petrol is known to last well beyond 150,000 miles. The OM651's life is defined by the timing chain — addressed proactively, it can comfortably reach 150,000+ miles. The M156 V8 is robust but demands expensive upkeep.

What is the difference between the W204, S204 and C204?

All three share the same platform and engines. The W204 is the 4‑door saloon (2007–2014, this page), the S204 is the 5‑door estate (2008–2014), and the C204 is the 2‑door coupé (2011–2015). Costs vary slightly by body style due to labour access — see each generation's own page for specifics.

How do I find my Mercedes W204 engine code?

Listed on the VIN plate (visible through the windscreen) and in the vehicle documentation. The code is stamped on the engine block — on OM651/OM646 it's on the front left, on M272/M276 it's on the right side. Tell us your variant and registration date, and we'll identify it for you.

W204 Engine Replacement Cost UK

Mercedes C‑Class W204 Engine Codes — The Complete Database

Every engine fitted to the W204 saloon specifically — including the pre‑facelift M272 V6 balance‑shaft risk and the post‑2011 M276 replacement.

Engine CodeFamilyFuelDisplacementPowerYears (W204 saloon)Variants (badges)Reliability2025 EnquiriesAvg. Recon Cost

M271.820 / .952M271Petrol, supercharged / CGI turbo1.8L156–184 PS2007–2014★★★☆☆ [PROVISIONAL — pending dedicated Engine Page]— (pattern data)

M272.921 / .911 / .947 / .948M272Petrol, naturally aspirated V62.5–3.0L204–231 PS2007–2010★★★☆☆ [PROVISIONAL — pending dedicated Engine Page]— (pattern data)

M276DE35M276Petrol, naturally aspirated V63.5L306 PS2011–2014★★★★☆ [PROVISIONAL — pending dedicated Engine Page]— (pattern data)

M156E63M156Petrol, naturally aspirated V86.2L457–517 PS2008–2014★★★☆☆ [PROVISIONAL — pending dedicated Engine Page]— (pattern data)

OM646DE22LAOM646Diesel, turbo I42.1L136–170 PS2007–2010★★★★☆ [PROVISIONAL — pending dedicated Engine Page]— (pattern data)

OM651DE22LAOM651Diesel, turbo I42.1L136–204 PS2009–2014★★★☆☆ [PROVISIONAL — pending dedicated Engine Page]1,250 family‑wide [MB‑VERIFIED]

OM642.910 / .961OM642Diesel, turbo V63.0L224–265 PS2007–2010★★★☆☆ [PROVISIONAL — pending dedicated Engine Page]880 family‑wide [MB‑VERIFIED]

Engine CodeFuelPowerYearsReliabilityEnquiriesAvg. Recon Cost

M271.820 / .952M271Petrol, supercharged / CGI turbo156–184 PS2007–2014★★★☆☆ [PROVISIONAL — pending dedicated Engine Page]— (pattern data)

M272.921 / .911 / .947 / .948M272Petrol, naturally aspirated V6204–231 PS2007–2010★★★☆☆ [PROVISIONAL — pending dedicated Engine Page]— (pattern data)

M276DE35M276Petrol, naturally aspirated V6306 PS2011–2014★★★★☆ [PROVISIONAL — pending dedicated Engine Page]— (pattern data)

M156E63M156Petrol, naturally aspirated V8457–517 PS2008–2014★★★☆☆ [PROVISIONAL — pending dedicated Engine Page]— (pattern data)

OM646DE22LAOM646Diesel, turbo I4136–170 PS2007–2010★★★★☆ [PROVISIONAL — pending dedicated Engine Page]— (pattern data)

OM651DE22LAOM651Diesel, turbo I4136–204 PS2009–2014★★★☆☆ [PROVISIONAL — pending dedicated Engine Page]1,250 family‑wide [MB‑VERIFIED]

OM642.910 / .961OM642Diesel, turbo V6224–265 PS2007–2010★★★☆☆ [PROVISIONAL — pending dedicated Engine Page]880 family‑wide [MB‑VERIFIED]

Overview

Mercedes C‑Class W204 — Overview

The W204 is the third generation of the Mercedes‑Benz C‑Class, produced from March 2007 to March 2014 as a four‑door saloon.

It introduced a stiffer body shell, an extended wheelbase, and design cues from the W221 S‑Class. A significant facelift in 2011 brought new engines — including the M276 V6 replacing the M272 — and updated styling. The W204 is available with rear‑wheel drive or 4MATIC all‑wheel drive, and its engine range spans from frugal four‑cylinder diesels to the 6.2‑litre M156 V8 in the C 63 AMG.

Key Facts

Platform

Mercedes‑Benz W204

Predecessor

W203

Successor

W205

Sibling body styles in this generation

S204 Estate (2008–2014), C204 Coupé (2011–2015)

Market Intelligence

No W204‑specific enquiry figure is available; OM651 diesel enquiries dominate the broader Mercedes compact‑car parc, with 1,250 UK requests in 2025 [MB‑VERIFIED].

Mercedes C‑Class W204 — Overview

The W204 is the third generation of the Mercedes‑Benz C‑Class, produced from March 2007 to March 2014 as a four‑door saloon.

It introduced a stiffer body shell, an extended wheelbase, and design cues from the W221 S‑Class. A significant facelift in 2011 brought new engines — including the M276 V6 replacing the M272 — and updated styling. The W204 is available with rear‑wheel drive or 4MATIC all‑wheel drive, and its engine range spans from frugal four‑cylinder diesels to the 6.2‑litre M156 V8 in the C 63 AMG.

Key Facts

Platform

Mercedes‑Benz W204

Predecessor

W203

Successor

W205

Sibling body styles in this generation

S204 Estate (2008–2014), C204 Coupé (2011–2015)

Market Intelligence

No W204‑specific enquiry figure is available; OM651 diesel enquiries dominate the broader Mercedes compact‑car parc, with 1,250 UK requests in 2025 [MB‑VERIFIED].

Best & Worst Engines

Best Diesel Overall

OM646DE22LA (C 200 CDI / C 220 CDI, pre‑2010)

“The 2.1‑litre four‑cylinder diesel — 136–170 PS, simple, robust, and lacking the rear‑mounted timing chain of its OM651 successor. The OM646 is the most dependable diesel in the entire W204 range.”

Who it's for: buyers who want a proven, low‑maintenance W204 diesel.

Best Petrol Overall

M276DE35 (C 350, post‑2011)

“The 3.5‑litre naturally aspirated V6 — 306 PS, smooth, and a significant improvement over the balance‑shaft‑prone M272. Post‑2011 M276 V6s are the safest petrol W204s to buy.”

Who it's for: buyers who want V6 refinement without the M272 balance‑shaft risk.

Highest Risk

M272 V6 (pre‑2009, C 230 / C 280 / C 300)

“Pre‑2009 M272 V6 petrols carry a well‑documented balance‑shaft gear wear issue that can be catastrophic if ignored. Always verify that the balance‑shaft gear has been replaced before buying.”

Who it's for: buyers willing to verify full engine history before purchase.

Most Expensive Failure

M156E63 (C 63 AMG)

“The 6.2‑litre AMG V8 — 457–517 PS, and a genuine performance icon. But cam lifter wear and head‑bolt issues on early cars can cost £1,500–£4,000 to fix. Budget for it.”

Who it's for: enthusiasts who understand the AMG tax.

Best Value

OM651DE22LA (C 220 CDI, post‑2011)

“The 2.1‑litre common‑rail diesel — 170 PS, strong economy, and the most popular W204 diesel. Provided the timing chain has been checked, this is the sweet spot of W204 ownership.”

Who it's for: the default choice for UK W204 buyers seeking economy and value.

Best Diesel Overall

OM646DE22LA (C 200 CDI / C 220 CDI, pre‑2010)

“The 2.1‑litre four‑cylinder diesel — 136–170 PS, simple, robust, and lacking the rear‑mounted timing chain of its OM651 successor. The OM646 is the most dependable diesel in the entire W204 range.”

Who it's for: buyers who want a proven, low‑maintenance W204 diesel.

Best Petrol Overall

M276DE35 (C 350, post‑2011)

“The 3.5‑litre naturally aspirated V6 — 306 PS, smooth, and a significant improvement over the balance‑shaft‑prone M272. Post‑2011 M276 V6s are the safest petrol W204s to buy.”

Who it's for: buyers who want V6 refinement without the M272 balance‑shaft risk.

Highest Risk

M272 V6 (pre‑2009, C 230 / C 280 / C 300)

“Pre‑2009 M272 V6 petrols carry a well‑documented balance‑shaft gear wear issue that can be catastrophic if ignored. Always verify that the balance‑shaft gear has been replaced before buying.”

Who it's for: buyers willing to verify full engine history before purchase.

Most Expensive Failure

M156E63 (C 63 AMG)

“The 6.2‑litre AMG V8 — 457–517 PS, and a genuine performance icon. But cam lifter wear and head‑bolt issues on early cars can cost £1,500–£4,000 to fix. Budget for it.”

Who it's for: enthusiasts who understand the AMG tax.

Best Value

OM651DE22LA (C 220 CDI, post‑2011)

“The 2.1‑litre common‑rail diesel — 170 PS, strong economy, and the most popular W204 diesel. Provided the timing chain has been checked, this is the sweet spot of W204 ownership.”

Who it's for: the default choice for UK W204 buyers seeking economy and value.

Mercedes C‑Class W204 — Ownership Economics

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

M271 (1.8 petrol)60k–100kTiming chain stretch£600–£1,500£1,500–£3,500

Watch the Chain — stretch is common

M272 (2.5–3.0 V6)60k–100kBalance‑shaft gear wear£1,200–£3,000£2,500–£5,000

Pre‑2009 Risk — verify repair history

M276 (3.5 V6)80k–150kThermostat, water pump£300–£800£3,000–£6,000

Solid Petrol — reliable post‑2011 V6

M156 (6.2 V8)40k–80kCam lifters, head bolts£1,500–£4,000£6,000–£12,000

AMG Tax — high performance, high cost

OM646 (2.1 diesel)100k–200kInjector seals, EGR£200–£600£2,500–£4,500

Proven Diesel — simple, robust

OM651 (2.1 diesel)80k–150kTiming chain stretch£600–£1,800£2,800–£5,500

Chain Risk — rear‑mounted chain is the key

OM642 (3.0 V6 diesel)80k–150kOil cooler seals£800–£1,500£3,200–£6,000

V6 Torque — smooth, but seals are labour‑intensive

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

M271 (1.8 petrol)60k–100kTiming chain stretch£600–£1,500£1,500–£3,500

Watch the Chain — stretch is common

M272 (2.5–3.0 V6)60k–100kBalance‑shaft gear wear£1,200–£3,000£2,500–£5,000

Pre‑2009 Risk — verify repair history

M276 (3.5 V6)80k–150kThermostat, water pump£300–£800£3,000–£6,000

Solid Petrol — reliable post‑2011 V6

M156 (6.2 V8)40k–80kCam lifters, head bolts£1,500–£4,000£6,000–£12,000

AMG Tax — high performance, high cost

OM646 (2.1 diesel)100k–200kInjector seals, EGR£200–£600£2,500–£4,500

Proven Diesel — simple, robust

OM651 (2.1 diesel)80k–150kTiming chain stretch£600–£1,800£2,800–£5,500

Chain Risk — rear‑mounted chain is the key

OM642 (3.0 V6 diesel)80k–150kOil cooler seals£800–£1,500£3,200–£6,000

V6 Torque — smooth, but seals are labour‑intensive

The W204 rule

A £2,800–£5,500 OM651 recon against a £4,000–£8,000 W204 sits at 35–140% of the car’s value. On a sub‑£5,000 example, that brushes our 70% Mercedes threshold — we’ll honestly tell you to walk away. Against a well‑kept £8,000+ example, the same recon drops to a routine 35–70% — a repair decision, not a financial one. Value the car first.

Key Takeaways

Which W204 Costs Least To Own?
OM646 2.1 diesel — simple, proven, cheap to fix.
Which W204 Costs Most To Own?
M156 6.2 V8 — AMG parts and labour are eye‑wateringly expensive.
Which W204 Is Best Value?
Post‑2011 C 220 CDI (OM651) — economy and torque, provided the chain has been checked.

Common Problems

01

M272

V6 Balance‑Shaft Gear Wear

Affected models:

W204 C 230, C 280, C 300 (pre‑2009 M272 V6).

Typical failure mileage:

60,000–100,000 miles.

Root cause:

The balance‑shaft gear on early M272 V6 engines has a soft sprocket that wears prematurely, causing the timing chain to stretch and the engine to run out of time. This is a well‑documented issue affecting pre‑2009 vehicles.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£2,500–£4,000

£1,200–£3,000

Replace balance‑shaft gear and chain

Catastrophic (Replacement)

Dealer

Specialist

£6,000–£9,000

£2,500–£5,000

Full reconditioned engine

Our Recommendation

If you’re buying a pre‑2009 W204 V6, verify that the balance‑shaft gear has been replaced — a £1,200–£3,000 repair is dramatically cheaper than the £2,500+ replacement that follows if the timing jumps. This is the single biggest buying‑guide red flag for early W204s.

Compare M272 engine prices for your W204

02

OM651

Timing‑Chain Stretch

Affected models:

W204 C 200 CDI, C 220 CDI, C 250 CDI (OM651 diesel, 2009–2014).

Typical failure mileage:

80,000–150,000 miles.

Root cause:

The OM651 has a rear‑mounted timing chain that can stretch over time. Cold‑start rattle is the classic early warning — if ignored, the chain can jump and cause catastrophic engine damage.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£1,200–£2,500

£600–£1,800

Replace chain, tensioner, guides

Catastrophic (Replacement)

Dealer

Specialist

£5,000–£7,500

£2,800–£5,500

Full reconditioned engine

Our Recommendation

At the first sign of cold‑start rattle on an OM651, get the chain inspected immediately — a £600–£1,800 preventative repair is far cheaper than the £2,800+ replacement that follows if ignored. On a W204 worth under £5,000, this decision alone determines whether the car stays economically viable.

Compare OM651 engine prices for your W204

03

OM642

Oil‑Cooler Seal Leak

Affected models:

W204 C 320 CDI (OM642 V6 diesel).

Typical failure mileage:

80,000–150,000 miles.

Root cause:

The oil‑cooler O‑rings in the V of the OM642 engine degrade with heat cycling, causing oil leaks that can drip onto the exhaust and create a burning smell. Labour is intensive as the intake manifold must be removed.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£1,500–£2,500

£800–£1,500

Replace oil‑cooler seals

Catastrophic (Replacement)

Dealer

Specialist

£5,000–£7,500

£3,200–£6,000

Full reconditioned engine

Our Recommendation

If you notice a burning oil smell or oil residue in the engine V, have the oil‑cooler seals replaced immediately — an £800–£1,500 repair is cheaper than the £3,200+ replacement that follows if the engine runs low on oil.

Compare OM642 engine prices for your W204

04

M156

Cam Lifter & Head‑Bolt Issues

Affected models:

W204 C 63 AMG (M156 V8).

Typical failure mileage:

40,000–80,000 miles.

Root cause:

Early M156 engines (2008–2010) can suffer from cam lifter wear and head‑bolt failure. Ticking from the top end is the classic warning sign — if ignored, catastrophic engine failure can occur.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£3,000–£5,000

£1,500–£4,000

Replace cam lifters and adjusters

Catastrophic (Replacement)

Dealer

Specialist

£12,000–£18,000

£6,000–£12,000

Full reconditioned engine

Our Recommendation

If you’re buying a pre‑2010 C 63 AMG, budget for a cam lifter inspection — a £1,500–£4,000 preventative repair is a fraction of the £6,000+ replacement that follows a full failure. This is the price of AMG ownership.

Compare M156 engine prices for your C 63 AMG

W204 Engine Replacement Costs — By Engine and Condition

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

C 180, C 200 (1.8 petrol)M271.820 / .952£800–£1,800£1,500–£3,500£2,500–£4,5008–12 hrs

C 230, C 280, C 300 (V6)M272£1,200–£2,800£2,500–£5,000£4,000–£7,00010–14 hrs

C 350 (post‑2011 V6)M276DE35£1,800–£3,200£3,000–£6,000£5,000–£8,00010–14 hrs

C 63 AMG (V8)M156E63£3,000–£6,000£6,000–£12,000£9,000–£16,00014–18 hrs

C 200 CDI, C 220 CDI (pre‑2010)OM646DE22LA£1,200–£2,500£2,500–£4,500£4,000–£6,0008–12 hrs

C 200 CDI, C 220 CDI, C 250 CDI (post‑2009)OM651DE22LA£1,500–£3,000£2,800–£5,500£4,500–£7,00010–14 hrs

C 320 CDI (V6 diesel)OM642.910 / .961£1,800–£3,500£3,200–£6,000£5,000–£8,50012–16 hrs

No Generation variance from the Model Page’s baseline figures — W204 shares its engine bay architecture with the S204 estate and C204 coupé, so costs are inherited directly per the Authority Model, with no divergence note required. OM651 and OM642 costs carried forward from the EM data’s Table A.

Core Variants

Diesel Variants

C 200 CDIC 220 CDIC 250 CDIC 320 CDI

Petrol Variants

C 180C 200C 230C 280C 300C 350C 63 AMG

Scope note: All variants listed are W204 saloon only. S204 Estate and C204 Coupé 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

C 200 CDIC 220 CDIC 250 CDIC 320 CDI

Petrol Variants

C 180C 200C 230C 280C 300C 350C 63 AMG

Scope note: All variants listed are W204 saloon only. S204 Estate and C204 Coupé 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)

Most Requested E90 Variants

Average E90 Replacement Cost

Most Common E90 Failures

FAQ

BMW 3 Series E90 rear three-quarter view

Why UK Mercedes W204 Owners Trust MercedesEngines.uk

Trusted W204 Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real W204 owners, as part of the Engine Finders network.
Compare W204 Engine Replacement Companies
see prices, warranty terms and supply‑&‑fit options side‑by‑side before you commit.
UK Engine Replacement Services for W204
covering every variant from C 180 to C 63 AMG, with supply‑only or full supply‑&‑fit available nationwide.

Find the best Mercedes W204 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 W204 Engine Prices on EnginesMarket

Why UK Mercedes W204 Owners Trust MercedesEngines.uk

Trusted W204 Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real W204 owners, as part of the Engine Finders network.
Compare W204 Engine Replacement Companies
see prices, warranty terms and supply‑&‑fit options side‑by‑side before you commit.
UK Engine Replacement Services for W204
covering every variant from C 180 to C 63 AMG, with supply‑only or full supply‑&‑fit available nationwide.

Find the best Mercedes W204 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 W204 Engine Prices on EnginesMarket

Mercedes C‑Class W204 Engines — The Complete UK Guide

Mercedes C‑Class W204 Engine Codes — The Complete Database

Mercedes C‑Class W204 — Overview

Mercedes C‑Class W204 — Overview

Best & Worst Engines

Mercedes C‑Class W204 — Ownership Economics

Common Problems

W204 Engine Replacement Costs — By Engine and Condition

Core Variants

Core Variants

Market Intelligence

FAQ

Why UK Mercedes W204 Owners Trust MercedesEngines.uk

Why UK Mercedes W204 Owners Trust MercedesEngines.uk