How much does a Mercedes W246 engine replacement cost in the UK?

A reconditioned W246 engine typically costs £1,200–£5,500 supply only [MB‑QUOTE], depending on engine — the OM607 1.5 diesel is the cheapest at £1,200–£2,800, while the OM651 2.1 diesel runs £3,200–£5,500. Fitting adds £650–£1,100. Use our calculator for a personalised quote.

What are the common problems with the Mercedes W246?

The OM651 timing‑chain tensioner is the single biggest risk — cold‑start rattle is the warning sign. M270 petrol engines suffer from water‑pump and coolant‑pipe leaks, while OM607 (1.5 diesel) units often develop injector wear. All W246 models can experience DPF clogging on diesel variants used mainly for short trips.

Is the Mercedes W246 reliable?

It depends heavily on the engine. Petrol M270 units are generally reliable with routine maintenance. The OM651 diesel is robust but carries a timing‑chain tensioner risk that requires proactive inspection. The OM607 (Renault K9K) is simpler and cheaper to maintain but injector wear is a known pattern. Overall, a well‑maintained W246 can be a dependable family car.

Which Mercedes W246 engine should I avoid?

No engine is an outright “avoid” — but a pre‑2015 OM651 without documented chain‑tensioner replacement is the one we consistently advise against. A neglected M270 petrol with persistent coolant leaks also warrants caution. Always insist on full service history and a pre‑purchase inspection by a specialist.

How do I know if my W246 engine needs replacing?

Key warning signs include: cold‑start rattle (OM651 chain), persistent coolant loss (M270 water pump), rough idle or hesitation (OM607 injectors), or blue smoke from the exhaust. If you experience any of these, have the car diagnosed immediately — catching a problem early saves thousands.

Is it worth replacing a Mercedes W246 engine, or should I scrap the car?

Depends on the car's value. Against a well‑kept £8,000 W246, a £3,200–£5,500 OM651 recon is 40–70% of the car's value — safe if the car is otherwise sound. Against a tired £4,000 example, the same recon is 80–140% — walk away. Our 70% Mercedes threshold is the line.

How long do Mercedes W246 engines last?

With proper servicing, the M270 petrol can exceed 150,000 miles, and the OM607 diesel is known to reach 200,000+ miles in Renault applications. The OM651's life is limited by the timing‑chain tensioner — addressed proactively, it can comfortably manage 150,000+ miles.

What is the difference between the W246, W245 and W247?

The W245 is the first‑generation B‑Class (2005–2011) with a taller, more MPV‑like body. The W246 (2012–2018) is the second generation on the MFA platform, sharing underpinnings with the A‑Class and GLA. The W247 (2019–present) is the third generation, built on the MFA2 platform with updated engines and tech.

How do I find my Mercedes W246 engine code?

Listed on the VIN plate (visible through the windscreen) and in the vehicle documentation. The code is also stamped on the engine block — on OM651 units it's on the front left, on M270 it's on the right side. Tell us your variant and registration year, and we'll identify it for you.

W246 Engine Replacement Cost UK

Mercedes B‑Class W246 Engine Codes — The Complete Database

Every engine fitted to the W246 hatchback specifically — including the Renault‑sourced OM607 diesel and the M270 petrol range.

Engine CodeFamilyFuelDisplacementPowerYears (W246)Variants (badges)Reliability2025 EnquiriesAvg. Recon Cost

M270DE16LAM270Petrol, turbo1.6L122–156 PS2011–2018★★★★☆ [PROVISIONAL — pending dedicated Engine Page]— (pattern data)

M270DE20LAM270Petrol, turbo2.0L156–211 PS2012–2018★★★★☆ [PROVISIONAL — pending dedicated Engine Page]— (pattern data)

OM607DE15LAOM607 (Renault K9K)Diesel, turbo1.5L90–109 PS2013–2018★★★★☆ [PROVISIONAL — pending dedicated Engine Page]— (pattern data)

OM651DE18LAOM651Diesel, turbo1.8L109 PS2011–2018★★★☆☆ [PROVISIONAL — inherited from Model Page]1,250 family‑wide [MB‑VERIFIED]

OM651DE22LAOM651Diesel, turbo2.1L136–170 PS2011–2018★★★☆☆ [PROVISIONAL — inherited from Model Page]1,250 family‑wide [MB‑VERIFIED]

Engine CodeFuelPowerYearsReliabilityEnquiriesAvg. Recon Cost

M270DE16LAM270Petrol, turbo122–156 PS2011–2018★★★★☆ [PROVISIONAL — pending dedicated Engine Page]— (pattern data)

M270DE20LAM270Petrol, turbo156–211 PS2012–2018★★★★☆ [PROVISIONAL — pending dedicated Engine Page]— (pattern data)

OM607DE15LAOM607 (Renault K9K)Diesel, turbo90–109 PS2013–2018★★★★☆ [PROVISIONAL — pending dedicated Engine Page]— (pattern data)

OM651DE18LAOM651Diesel, turbo109 PS2011–2018★★★☆☆ [PROVISIONAL — inherited from Model Page]1,250 family‑wide [MB‑VERIFIED]

OM651DE22LAOM651Diesel, turbo136–170 PS2011–2018★★★☆☆ [PROVISIONAL — inherited from Model Page]1,250 family‑wide [MB‑VERIFIED]

Overview

Mercedes B‑Class W246 — Overview

The W246 is the second generation of the Mercedes‑Benz B‑Class, a five‑door hatchback produced from late 2011 to late 2018.

Built on the Mercedes‑Benz MFA platform, it shares its underpinnings with the W176 A‑Class, X156 GLA, and C117 CLA. The W246 was offered with a choice of petrol, diesel, and natural‑gas engines, plus a battery‑electric variant (W242). It is classified as a small MPV by Euro NCAP.

Key Facts

Platform

Mercedes‑Benz MFA

Predecessor

W245

Successor

W247

Sibling body styles in this generation

none (W246 is a single 5‑door hatchback body style)

Market Intelligence

No W246‑specific enquiry figure is available; <a href='https://mercedesengines.uk/engine/om651'>OM651</a> diesel enquiries dominate the broader Mercedes compact‑car parc, with 1,250 UK requests in 2025 [MB‑VERIFIED].

Mercedes B‑Class W246 — Overview

The W246 is the second generation of the Mercedes‑Benz B‑Class, a five‑door hatchback produced from late 2011 to late 2018.

Built on the Mercedes‑Benz MFA platform, it shares its underpinnings with the W176 A‑Class, X156 GLA, and C117 CLA. The W246 was offered with a choice of petrol, diesel, and natural‑gas engines, plus a battery‑electric variant (W242). It is classified as a small MPV by Euro NCAP.

Key Facts

Platform

Mercedes‑Benz MFA

Predecessor

W245

Successor

W247

Sibling body styles in this generation

none (W246 is a single 5‑door hatchback body style)

Market Intelligence

No W246‑specific enquiry figure is available; <a href='https://mercedesengines.uk/engine/om651'>OM651</a> diesel enquiries dominate the broader Mercedes compact‑car parc, with 1,250 UK requests in 2025 [MB‑VERIFIED].

Best & Worst Engines

Best Diesel Overall

OM651DE22LA (B200 CDI / B220 CDI)

“The 2.1‑litre four‑cylinder diesel — 136–170 PS, up to 350 Nm of torque, and the workhorse of the W246 diesel range. The OM651 is a proven unit but carries a timing‑chain tensioner weakness that, if caught early, is a manageable repair.”

Who it's for: buyers who want the best balance of economy and power in their W246 diesel.

Best Petrol Overall

M270DE16LA (B180 / B200)

“The 1.6‑litre turbo petrol — 122–156 PS, smooth, and the most dependable choice in the W246 range. It has no timing‑chain weakness and its cooling‑system issues are well‑understood and relatively inexpensive to fix.”

Who it's for: buyers who want petrol refinement without diesel chain worries.

Highest Risk

OM651DE18LA / OM651DE22LA (pre‑2015)

“The OM651's rear‑mounted timing chain and tensioner are well‑documented weak points. Cold‑start rattle is the warning sign. Pre‑2015 W246 diesels without documented chain‑tensioner replacement are the highest‑risk purchase in the range.”

Who it's for: buyers on a tighter budget who understand the OM651's reputation and can verify chain history.

Budget Diesel

OM607DE15LA (B160 CDI / B180 CDI)

“The Renault‑sourced 1.5‑litre diesel is simpler and cheaper to maintain than the OM651. Injector wear is a known pattern but repairs are inexpensive. A practical choice for budget‑conscious W246 owners.”

Who it's for: buyers who prioritise low running costs and urban economy.

Best Value

M270DE16LA (B180 / B200)

“The 1.6‑litre petrol turbo — reliable, no chain risk, and cheaper to buy and maintain than the 2.0‑litre. For most UK W246 buyers, this is the safest all‑round bet.”

Who it's for: the default choice for W246 buyers who want the best balance of reliability and running costs.

Best Diesel Overall

OM651DE22LA (B200 CDI / B220 CDI)

“The 2.1‑litre four‑cylinder diesel — 136–170 PS, up to 350 Nm of torque, and the workhorse of the W246 diesel range. The OM651 is a proven unit but carries a timing‑chain tensioner weakness that, if caught early, is a manageable repair.”

Who it's for: buyers who want the best balance of economy and power in their W246 diesel.

Best Petrol Overall

M270DE16LA (B180 / B200)

“The 1.6‑litre turbo petrol — 122–156 PS, smooth, and the most dependable choice in the W246 range. It has no timing‑chain weakness and its cooling‑system issues are well‑understood and relatively inexpensive to fix.”

Who it's for: buyers who want petrol refinement without diesel chain worries.

Highest Risk

OM651DE18LA / OM651DE22LA (pre‑2015)

“The OM651's rear‑mounted timing chain and tensioner are well‑documented weak points. Cold‑start rattle is the warning sign. Pre‑2015 W246 diesels without documented chain‑tensioner replacement are the highest‑risk purchase in the range.”

Who it's for: buyers on a tighter budget who understand the OM651's reputation and can verify chain history.

Budget Diesel

OM607DE15LA (B160 CDI / B180 CDI)

“The Renault‑sourced 1.5‑litre diesel is simpler and cheaper to maintain than the OM651. Injector wear is a known pattern but repairs are inexpensive. A practical choice for budget‑conscious W246 owners.”

Who it's for: buyers who prioritise low running costs and urban economy.

Best Value

M270DE16LA (B180 / B200)

“The 1.6‑litre petrol turbo — reliable, no chain risk, and cheaper to buy and maintain than the 2.0‑litre. For most UK W246 buyers, this is the safest all‑round bet.”

Who it's for: the default choice for W246 buyers who want the best balance of reliability and running costs.

Mercedes B‑Class W246 — Ownership Economics

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

M270DE16LA60k–100kWater pump, carbon build‑up£300–£600£1,500–£3,200

Solid Petrol — reliable, simple turbo

M270DE20LA60k–100kWater pump, carbon build‑up£300–£600£2,000–£4,500

Strong Performer — more power, same upkeep

OM607DE15LA80k–150kInjector wear, EGR clogging£200–£500£1,200–£2,800

Budget Diesel — cheap to run, cheap to fix

OM651DE18LA80k–150kTiming‑chain tensioner£600–£1,500£2,800–£4,800

Watch the Chain — tensioner is the key risk

OM651DE22LA80k–150kTiming‑chain tensioner£600–£1,500£3,200–£5,500

Best Diesel — torque and economy, if chain is sound

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

M270DE16LA60k–100kWater pump, carbon build‑up£300–£600£1,500–£3,200

Solid Petrol — reliable, simple turbo

M270DE20LA60k–100kWater pump, carbon build‑up£300–£600£2,000–£4,500

Strong Performer — more power, same upkeep

OM607DE15LA80k–150kInjector wear, EGR clogging£200–£500£1,200–£2,800

Budget Diesel — cheap to run, cheap to fix

OM651DE18LA80k–150kTiming‑chain tensioner£600–£1,500£2,800–£4,800

Watch the Chain — tensioner is the key risk

OM651DE22LA80k–150kTiming‑chain tensioner£600–£1,500£3,200–£5,500

Best Diesel — torque and economy, if chain is sound

The W246 rule

A £2,800–£4,800 OM651 recon against a £6,000 W246 sits at 47–80% 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 35–60% — a repair decision, not a financial one. Value the car first.

Key Takeaways

Which W246 Costs Least To Own?
OM607 1.5 diesel — cheapest recon and simple repairs.
Which W246 Costs Most To Own?
OM651 2.1 diesel — timing‑chain tensioner work is labour‑intensive.
Which W246 Is Best Value?
M270 1.6 petrol — reliable, no chain risk, and cheaper than the 2.0‑litre.

Common Problems

01

OM651

Timing‑Chain Tensioner Wear

Affected models:

W246 B180 CDI, B200 CDI, B220 CDI (all OM651 variants).

Typical failure mileage:

80,000–150,000 miles.

Root cause:

The timing‑chain tensioner can wear prematurely, leading to chain slack and, in severe cases, catastrophic engine failure. Cold‑start rattle is the classic early warning.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£1,200–£2,500

£600–£1,500

Replace tensioner, chain, 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, get the chain tensioner inspected immediately — a £600–£1,500 preventative repair is dramatically cheaper than the £2,800–£5,500 replacement that follows if ignored. On a W246 worth under £5,000, this decision alone determines whether the car stays economically viable.

Compare OM651 engine prices for your W246

02

M270

Water Pump & Coolant Leaks

Affected models:

W246 B180, B200, B220 4MATIC, B250 (all M270 petrol variants).

Typical failure mileage:

60,000–100,000 miles.

Root cause:

The plastic water pump housing and coolant crossover pipes can crack with age and heat cycling, leading to gradual coolant loss and potential overheating.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£600–£1,000

£300–£600

Water pump replacement, coolant flush

Catastrophic (Replacement)

Dealer

Specialist

£1,500–£3,000

£800–£1,800

Head gasket repair if overheated

Our Recommendation

Have the cooling system inspected at every service — a £300–£600 water pump replacement is cheap insurance against a £1,500+ head‑gasket repair if the engine overheats.

Compare M270 engine prices for your W246

03

OM607

Injector Wear (Renault K9K)

Affected models:

W246 B160 CDI, B180 CDI (OM607 1.5 diesel).

Typical failure mileage:

80,000–150,000 miles.

Root cause:

Injector wear and electrical faults are common on the Renault‑sourced K9K unit, leading to rough idle, poor economy, and increased emissions.

Tiered Cost Table

Preventative (Repair)

Dealer

Specialist

£500–£1,000

£200–£500

Injector cleaning or replacement set

Catastrophic (Replacement)

Dealer

Specialist

£2,500–£4,000

£1,200–£2,800

Full reconditioned engine

Our Recommendation

If your OM607‑powered W246 develops a rough idle or hesitation, have the injectors tested immediately — a £200–£500 repair is far cheaper than the £1,200+ replacement that follows a full failure.

Compare OM607 engine prices for your W246

W246 Engine Replacement Costs — By Engine and Condition

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

B180, B200 (petrol)M270DE16LA£800–£1,800£1,500–£3,200£2,500–£4,5008–12 hrs

B200 NGD, B220 4MATIC, B250M270DE20LA£1,200–£2,500£2,000–£4,500£3,500–£6,00010–14 hrs

B160 CDI, B180 CDI (1.5)OM607DE15LA£600–£1,200£1,200–£2,800£2,000–£4,0008–10 hrs

B180 CDI (1.8)OM651DE18LA£1,500–£2,800£2,800–£4,800£4,000–£6,50010–14 hrs

B200 CDI, B220 CDIOM651DE22LA£1,800–£3,200£3,200–£5,500£4,500–£7,00012–16 hrs

No Generation variance from the Model Page’s baseline figures — W246 shares its engine bay architecture with the W176 A‑Class and X156 GLA, so costs are inherited directly per the Authority Model, with no divergence note required. OM651 costs carried forward from the EM data’s Table A.

Core Variants

Diesel Variants

B160 CDIB180 CDIB200 CDIB220 CDI

Petrol Variants

B180B200B220 4MATICB250

Scope note: All variants listed are W246 5‑door hatchback only. The W242 Electric Drive is a separate model and is not covered on this page.

Core Variants

Diesel Variants

B160 CDIB180 CDIB200 CDIB220 CDI

Petrol Variants

B180B200B220 4MATICB250

Scope note: All variants listed are W246 5‑door hatchback only. The W242 Electric Drive is a separate model and is not covered on this page.

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 W246 Owners Trust MercedesEngines.uk

Trusted W246 Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real W246 owners, as part of the Engine Finders network.
Compare W246 Engine Replacement Companies
see prices, warranty terms and supply‑&‑fit options side‑by‑side before you commit.
UK Engine Replacement Services for W246
covering every variant from B160 CDI to B250, with supply‑only or full supply‑&‑fit available nationwide.

Find the best Mercedes W246 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 B‑Class W246 Engine Prices on EnginesMarket

Why UK Mercedes W246 Owners Trust MercedesEngines.uk

Trusted W246 Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real W246 owners, as part of the Engine Finders network.
Compare W246 Engine Replacement Companies
see prices, warranty terms and supply‑&‑fit options side‑by‑side before you commit.
UK Engine Replacement Services for W246
covering every variant from B160 CDI to B250, with supply‑only or full supply‑&‑fit available nationwide.

Find the best Mercedes W246 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 B‑Class W246 Engine Prices on EnginesMarket

Mercedes B‑Class W246 Engines — The Complete UK Guide

Mercedes B‑Class W246 Engine Codes — The Complete Database

Mercedes B‑Class W246 — Overview

Mercedes B‑Class W246 — Overview

Best & Worst Engines

Mercedes B‑Class W246 — Ownership Economics

Common Problems

W246 Engine Replacement Costs — By Engine and Condition

Core Variants

Core Variants

Market Intelligence

FAQ

Why UK Mercedes W246 Owners Trust MercedesEngines.uk

Why UK Mercedes W246 Owners Trust MercedesEngines.uk