How much does a Mercedes‑Benz C‑Class W205 engine replacement cost in the UK?

A reconditioned W205 engine typically costs £1,500–£14,000 supply only, depending on engine — the volume M274 four‑cylinder petrol sits at £1,500–£2,800, while the AMG M177 V8 commands £8,000–£14,000. Fitting adds £650–£1,500. Use our calculator for a personalised figure.

Which Mercedes‑Benz C‑Class W205 engine is the most reliable?

The OM654 (post‑facelift diesel, 2018–2021) is the most improved — it replaces the OM651 with a better timing chain design and eliminates the 'Black Death' injector seal issue. Among petrols, the M274 four‑cylinder turbo is proven and robust, with timing chain stretch as its only real watchpoint.

What are the common problems with the Mercedes‑Benz C‑Class W205?

Injector seal 'Black Death' on the OM651 diesel (pre‑facelift), AdBlue system failures on the OM654 diesel (post‑facelift), timing chain stretch on the M274 petrol four‑cylinder, and sensor‑derived misfire issues on the M177 V8 (AMG C 63/S).

Is the Mercedes‑Benz C‑Class W205 reliable?

It depends heavily on which engine and which side of the September 2018 facelift your car sits on. Pre‑facelift diesel buyers get the ageing but proven OM651; post‑facelift buyers get the improved OM654. The petrol M274 is a solid choice across the board, while the AMG V8 demands a maintenance budget to match its performance.

Which Mercedes‑Benz C‑Class W205 engine should I avoid?

No engine outright — but a pre‑facelift OM651 without documented injector seal history is the one we consistently advise buyers to inspect carefully. A neglected M177 AMG V8 without service history is the second, as sensor misfires can be expensive to diagnose.

How do I know if my Mercedes‑Benz C‑Class W205 engine needs replacing?

Cold‑start rattle (M274 timing chain), rough idle or diesel smell (OM651 injector seals), AdBlue countdown warnings (OM654), or misfires under load (M177) are the key warning signs. Use our diagnostic calculator for a personalised assessment.

Is it worth replacing a Mercedes‑Benz C‑Class W205 engine, or should I scrap the car?

Depends on the car's value. Against a well‑kept £15,000 W205, a £4,000 OM654 recon is 27% of the car's value — safe. Against a tired £6,000 example, the same recon is 67% — on the border of the 70% Mercedes‑Benz threshold. Value the car and its history first.

How long do Mercedes‑Benz C‑Class W205 engines last?

The OM651 diesel can exceed 200,000 miles with proper servicing, though injector seals are a recurring maintenance item. The OM654 is similarly durable, with AdBlue system maintenance its main cost. The M274 petrol four can comfortably reach 150,000+ miles with regular oil changes.

What is the difference between the W205 saloon and the S205/C205/A205?

All four share the W205 generation platform and most engines. The W205 is the 4‑door saloon (2014–2021, this page), the S205 is the Estate (2014–2021), the C205 is the 2‑door coupé (2015–2023), and the A205 is the 2‑door cabriolet (2016–2023). Costs vary slightly by body style due to labour access — see each generation's own page for specifics.

How do I find my Mercedes‑Benz C‑Class W205 engine code?

Listed on the VIN plate and vehicle documentation; block stamping is visible from below on most engines. Tell us your variant and approximate registration date (pre‑ or post‑September 2018) and we'll identify it — 25+ vetted Mercedes specialists will confirm it for free.

W205 Engine Replacement Cost UK

Name: Mercedes‑Benz C‑Class W205 UK Engine Enquiry Data 2025
Creator: MercedesEngines.uk

Mercedes‑Benz C‑Class W205 Engine Codes — The Complete Database

Engine CodeFuelPowerYearsReliabilityEnquiriesAvg. Recon Cost

Overview

Mercedes‑Benz C‑Class W205 — Overview

The W205 is the fourth generation of the Mercedes‑Benz C‑Class, launched in 2014 as the successor to the W204.

It introduced a significantly lighter body structure using aluminium and high‑strength steel, resulting in a 100kg weight saving. A major September 2018 facelift brought more than cosmetic changes: it replaced the ageing OM651 diesel four with the all‑new OM654, and introduced the M264 mild‑hybrid petrol engine — splitting this generation's ownership story into two genuinely different mechanical eras under one body code.

Key Facts

Platform

Mercedes‑Benz MRA (Modular Rear Architecture)

Predecessor

W204

Successor

W206

Sibling body styles in this generation

S205 Estate, C205 Coupé, A205 Cabriolet

Market Intelligence

The W205 saloon generated 368 real UK engine enquiries in 2025 [MB‑VERIFIED], concentrated on the OM651 diesel as the parc exits warranty age.

Mercedes‑Benz C‑Class W205 — Overview

The W205 is the fourth generation of the Mercedes‑Benz C‑Class, launched in 2014 as the successor to the W204.

It introduced a significantly lighter body structure using aluminium and high‑strength steel, resulting in a 100kg weight saving. A major September 2018 facelift brought more than cosmetic changes: it replaced the ageing OM651 diesel four with the all‑new OM654, and introduced the M264 mild‑hybrid petrol engine — splitting this generation's ownership story into two genuinely different mechanical eras under one body code.

Key Facts

Platform

Mercedes‑Benz MRA (Modular Rear Architecture)

Predecessor

W204

Successor

W206

Sibling body styles in this generation

S205 Estate, C205 Coupé, A205 Cabriolet

Market Intelligence

The W205 saloon generated 368 real UK engine enquiries in 2025 [MB‑VERIFIED], concentrated on the OM651 diesel as the parc exits warranty age.

Best & Worst Engines

Best Diesel Overall

OM654 (post‑facelift, 2018–2021)

“The modern 2.0‑litre diesel that replaced the OM651. Significantly improved timing chain design, better fuel economy, and none of the 'Black Death' injector seal issues that plagued its predecessor. AdBlue system niggles are its only real demand.”

Who it's for: buyers who want modern diesel efficiency without the OM651's caveats.

Best Petrol Overall

M274 2.0‑litre turbo (184–245hp)

“Mercedes' workhorse four‑cylinder turbo — smooth, responsive, and fundamentally robust. Chain stretch is the main watchpoint, but it's far less common than the N47 problems BMW owners face.”

Who it's for: buyers who want everyday usability with genuine performance.

Highest Risk

OM651 2.1‑litre diesel (pre‑facelift, 2014–2018)

“Injector seal failure ('Black Death') and timing chain tensioner wear are this generation's defining diesel risks — both are well‑documented and expensive to address if ignored.”

Who it's for: only buyers with full service history and documented injector work.

Most Expensive Failure

M177 4.0‑litre V8 (AMG C 63/S)

“The hot‑vee twin‑turbo V8 shares the M178's cooling demands. Sensor‑derived misfire issues are the main electrical headache, and tight engine bay packaging makes even sensor replacement labour‑intensive.”

Who it's for: AMG buyers with deep pockets and a trusted specialist.

Best Value

M274 2.0‑litre turbo (C 200, 184hp)

“The volume petrol engine in the W205 range — parts are widely available, the tuning is proven, and it delivers 184hp with genuine everyday usability. Chain stretch is the only real watchpoint.”

Who it's for: buyers who want the W205 experience without the diesel's complications or the V6's running costs.

Most Overlooked

M276 3.0‑litre V6 bi‑turbo (C 400 / C 450 AMG)

“The 3.0‑litre V6 bi‑turbo sits in a sweet spot between the four‑cylinder and the full‑fat AMG V8 — 333–367hp, smooth power delivery, and without the M177's hot‑vee cooling demands.”

Who it's for: buyers who want V6 refinement without the AMG V8's maintenance premium.

Best Diesel Overall

OM654 (post‑facelift, 2018–2021)

“The modern 2.0‑litre diesel that replaced the OM651. Significantly improved timing chain design, better fuel economy, and none of the 'Black Death' injector seal issues that plagued its predecessor. AdBlue system niggles are its only real demand.”

Who it's for: buyers who want modern diesel efficiency without the OM651's caveats.

Best Petrol Overall

M274 2.0‑litre turbo (184–245hp)

“Mercedes' workhorse four‑cylinder turbo — smooth, responsive, and fundamentally robust. Chain stretch is the main watchpoint, but it's far less common than the N47 problems BMW owners face.”

Who it's for: buyers who want everyday usability with genuine performance.

Highest Risk

OM651 2.1‑litre diesel (pre‑facelift, 2014–2018)

“Injector seal failure ('Black Death') and timing chain tensioner wear are this generation's defining diesel risks — both are well‑documented and expensive to address if ignored.”

Who it's for: only buyers with full service history and documented injector work.

Most Expensive Failure

M177 4.0‑litre V8 (AMG C 63/S)

“The hot‑vee twin‑turbo V8 shares the M178's cooling demands. Sensor‑derived misfire issues are the main electrical headache, and tight engine bay packaging makes even sensor replacement labour‑intensive.”

Who it's for: AMG buyers with deep pockets and a trusted specialist.

Best Value

M274 2.0‑litre turbo (C 200, 184hp)

“The volume petrol engine in the W205 range — parts are widely available, the tuning is proven, and it delivers 184hp with genuine everyday usability. Chain stretch is the only real watchpoint.”

Who it's for: buyers who want the W205 experience without the diesel's complications or the V6's running costs.

Most Overlooked

M276 3.0‑litre V6 bi‑turbo (C 400 / C 450 AMG)

“The 3.0‑litre V6 bi‑turbo sits in a sweet spot between the four‑cylinder and the full‑fat AMG V8 — 333–367hp, smooth power delivery, and without the M177's hot‑vee cooling demands.”

Who it's for: buyers who want V6 refinement without the AMG V8's maintenance premium.

Mercedes‑Benz C‑Class W205 — Ownership Economics

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

M274 1.6/2.0T60k–100kTiming chain stretch£800–£1,500£1,500–£2,800

Solid Choice — proven four‑cylinder turbo

M264 2.0T (mild‑hybrid)40k–80k48V system issues£500–£1,200£1,800–£3,200

Modern Tech — complex but well‑supported

M276 3.0 V6 bi‑turbo50k–90kTiming chain / oil leaks£1,000–£2,500£3,800–£6,500

V6 Smooth — more complex, more costly

OM651 2.1 d80k–150kInjector seals ("Black Death"), timing chain£400–£1,500£2,800–£4,800

Best Diesel (pre‑LCI) — proven but ageing

OM654 2.0 d80k–120kAdBlue system, EGR cooler£500–£1,500£3,000–£5,000

Modern Diesel — improved over OM651

M177 4.0 V8 bi‑turbo30k–60kSensor misfires, cooling system£1,000–£3,000£8,000–£14,000

AMG Performance — highest running costs

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

M274 1.6/2.0T60k–100kTiming chain stretch£800–£1,500£1,500–£2,800

Solid Choice — proven four‑cylinder turbo

M264 2.0T (mild‑hybrid)40k–80k48V system issues£500–£1,200£1,800–£3,200

Modern Tech — complex but well‑supported

M276 3.0 V6 bi‑turbo50k–90kTiming chain / oil leaks£1,000–£2,500£3,800–£6,500

V6 Smooth — more complex, more costly

OM651 2.1 d80k–150kInjector seals ("Black Death"), timing chain£400–£1,500£2,800–£4,800

Best Diesel (pre‑LCI) — proven but ageing

OM654 2.0 d80k–120kAdBlue system, EGR cooler£500–£1,500£3,000–£5,000

Modern Diesel — improved over OM651

M177 4.0 V8 bi‑turbo30k–60kSensor misfires, cooling system£1,000–£3,000£8,000–£14,000

AMG Performance — highest running costs

The W205 rule

A £3,000–£5,000 OM654 recon against a £10,000–£15,000 W205 sits at 20–50% of the car's value — well inside the 70% Mercedes‑Benz threshold. Against a £30,000+ facelift example, the same recon drops to 10–17% — a routine repair decision, not a financial one. Value the car and its service history first.

Common Problems

01

OM651

Injector Seal Failure ("Black Death")

Affected models:

W205 C 220 d, C 250 d (pre‑facelift, 2014–2018).

OM651 Injector Seal Failure ("Black Death")

Typical failure mileage:

80,000–150,000 miles.

Root cause:

The injector seal fails, allowing combustion gases to leak past and carbon to build up around the injector — the "black death" nickname comes from the tar‑like carbon residue that forms.

Tiered Cost Table

Our Recommendation

At the first sign of rough idle or diesel smell in the cabin, get injector seals inspected immediately — a £400–£1,200 seal replacement is dramatically cheaper than the £2,800–£4,800 replacement that follows if ignored.

Compare OM651 engine prices for your W205

02

OM654

AdBlue System Failure

Affected models:

W205 C 220 d (post‑facelift, 2018–2021).

Typical failure mileage:

80,000–120,000 miles.

Root cause:

The AdBlue system's NOx sensors, heater elements, and dosing valves can fail — leading to countdown warnings that prevent the car from restarting.

Tiered Cost Table

Our Recommendation

A £500–£1,500 AdBlue system service is non‑negotiable on the OM654 — the countdown warnings give you limited mileage before the car won't restart.

Compare OM654 engine prices for your W205

03

M274

Timing Chain Stretch

Affected models:

W205 C 180, C 200, C 250, C 300 (all M274 petrols).

Typical failure mileage:

60,000–100,000 miles.

Root cause:

The timing chain stretches over time, particularly on engines with extended service intervals — a rattle on cold start is the classic early warning.

Tiered Cost Table

Our Recommendation

At the first sign of cold‑start rattle, get the chain inspected immediately — an £800–£1,500 preventative repair is far cheaper than the £2,500–£4,000 replacement that follows if ignored.

Compare M274 engine prices for your W205

04

M177

Sensor‑Derived Misfire Issues

Affected models:

W205 AMG C 63, C 63 S (all M177 V8s).

Typical failure mileage:

30,000–60,000 miles.

Root cause:

The hot‑vee V8 is known for occasional sensor‑derived misfire issues — tight packaging in the engine bay means sensor replacement can lead to a costly labour bill.

Tiered Cost Table

Our Recommendation

On a £25,000–£40,000 AMG C 63, a £1,000–£2,000 sensor diagnosis is cheap insurance — it protects the £10,000–£15,000 engine that sits at the heart of the car.

Compare M177 engine prices for your AMG C 63

W205 Engine Replacement Costs — By Engine and Condition

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

C 180 (1.6T)M274.910£800–£1,500£1,500–£2,800£2,500–£4,0008–12 hrs

C 200 (2.0T)M274.920£800–£1,500£1,500–£2,800£2,500–£4,0008–12 hrs

C 250 (2.0T)M274.920£800–£1,500£1,500–£2,800£2,500–£4,0008–12 hrs

C 300 (2.0T)M274.920 / M264.920£900–£1,800£1,800–£3,200£3,000–£4,5008–12 hrs

C 300 (facelift)M264.920£1,000–£1,800£1,800–£3,200£3,000–£5,0008–12 hrs

C 400 4MATIC (3.0 V6)M276.823£2,000–£3,500£3,800–£6,500£5,500–£8,50012–16 hrs

C 450 AMG (3.0 V6)M276.823£2,000–£3,500£3,800–£6,500£5,500–£8,50012–16 hrs

C 220 d / C 250 d (pre‑LCI)OM651£1,500–£2,800£2,800–£4,800£4,000–£6,00010–14 hrs

C 220 d (post‑LCI)OM654.920£1,800–£3,000£3,000–£5,000£4,200–£6,50010–14 hrs

AMG C 63M177.980£5,000–£8,000£8,000–£14,000£12,000–£18,00016–22 hrs

AMG C 63 SM177.980£5,000–£8,000£8,000–£14,000£12,000–£18,00016–22 hrs

Core Variants

Diesel Variants

C 220 dC 250 d

Petrol Variants

C 180C 200C 250C 300C 400C 450 AMGAMG C 63AMG C 63 S

Scope note: All variants listed are W205 saloon only. S205 Estate, C205 Coupé and A205 Cabriolet share most of these engines but are covered on their own Generation Pages, since fitment and production years vary by body style.

Core Variants

Diesel Variants

C 220 dC 250 d

Petrol Variants

C 180C 200C 250C 300C 400C 450 AMGAMG C 63AMG C 63 S

Scope note: All variants listed are W205 saloon only. S205 Estate, C205 Coupé and A205 Cabriolet share most of these engines but are covered on their own Generation Pages, since fitment and production years vary by body style.

Market Intelligence

Most Requested E90 Engines (2025)

1.1. OM651 (1,250 [MB‑VERIFIED] across C‑Class/E‑Class) · 2. OM654 (520 [MB‑VERIFIED] across C/E/GLC 200d/220d) · 3. M274 (pattern data)

Most Requested E90 Variants

1.1. C 220 d · 2. C 200 · 3. AMG C 63 S

Average E90 Replacement Cost

£3,900 reconditioned, supply only [MB‑QUOTE]

Most Common E90 Failures

1.1. OM651 injector seal "Black Death" · 2. OM654 AdBlue system · 3. M274 timing chain stretch

Live Feed

VehicleLocationIssueEnquiries

Mercedes C 220 d W205 (OM651)

Manchester

Rough idle / diesel smell

12

enquiries

Mercedes C 200 W205 (M274)

Birmingham

Cold‑start rattle

8

enquiries

Mercedes AMG C 63 S W205 (M177)

London

Misfire under load

4

enquiries

Updated Monthly

FAQ

BMW 3 Series E90 rear three-quarter view

Why UK Mercedes‑Benz C‑Class W205 Owners Trust MercedesEngines.uk

Trusted W205 Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real W205 owners, as part of the Engine Finders network.
Compare W205 Engine Replacement Companies
see prices, warranty terms and supply‑and‑fit options side‑by‑side before you commit.
UK Engine Replacement Services for W205
covering every variant from C 180 to AMG C 63 S, with supply‑only or full supply‑and‑fit available nationwide.

Find the best Mercedes‑Benz C‑Class W205 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‑Benz C‑Class W205 Engine Prices on EnginesMarket

Why UK Mercedes‑Benz C‑Class W205 Owners Trust MercedesEngines.uk

Trusted W205 Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real W205 owners, as part of the Engine Finders network.
Compare W205 Engine Replacement Companies
see prices, warranty terms and supply‑and‑fit options side‑by‑side before you commit.
UK Engine Replacement Services for W205
covering every variant from C 180 to AMG C 63 S, with supply‑only or full supply‑and‑fit available nationwide.

Find the best Mercedes‑Benz C‑Class W205 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‑Benz C‑Class W205 Engine Prices on EnginesMarket

Mercedes‑Benz C‑Class W205 Engines — The Complete UK Guide

Mercedes‑Benz C‑Class W205 Engine Codes — The Complete Database

Mercedes‑Benz C‑Class W205 — Overview

Mercedes‑Benz C‑Class W205 — Overview

Best & Worst Engines

Mercedes‑Benz C‑Class W205 — Ownership Economics

Common Problems

W205 Engine Replacement Costs — By Engine and Condition

Core Variants

Core Variants

Market Intelligence

FAQ

Why UK Mercedes‑Benz C‑Class W205 Owners Trust MercedesEngines.uk

Why UK Mercedes‑Benz C‑Class W205 Owners Trust MercedesEngines.uk