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Mercedes-Benz B180 CDI Specialists

Mercedes-Benz B Class B180 CDI Engine Replacement Compare Prices & Get Quotes

Get quotes today from trusted UK Mercedes-Benz B Class B180 CDI engine specialists. Compare prices on reconditioned, rebuilt and used engines for both the W245 (2005-2011) and W246 (2011-2018) generations - supply & fit available across the UK.

Supply & Fit Available
12-Month Warranty
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Mercedes-Benz B Class B180 CDI Engine
from£1,800 to £2,800
  • Usedfrom £900
  • Reconditionedfrom £1,500
  • Common codesOM640.940, OM651.901
Mercedes Benz b-class Mercedes-Benz B Class B180 CDI Used Engine — OM640.940Mercedes Benz b-classUsed Engine — OM640.940Mercedes Benz b-class Mercedes-Benz B Class B180 CDI Reconditioned Engine — OM640.940Mercedes Benz b-classReconditioned Engine — OM640.940Mercedes Benz b-class Mercedes-Benz B Class B180 CDI Rebuilt Engine — OM640.940Mercedes Benz b-classRebuilt Engine — OM640.940

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3 Simple Steps to Finding the Right Replacement Engine

Clear information first, then the right engine and specialist for your exact vehicle.

Variant History

Mercedes-Benz B Class B180 CDI Engine History & Specs at a Glance

The Mercedes-Benz B Class B180 CDI entered the UK market in September 2005 as the entry-level diesel in the first-generation W245 range. Powered initially by a 2.0-litre OM640.940 diesel producing 109bhp, the B180 CDI was repositioned in 2011 with the second-generation W246, switching to the 1.8-litre OM651.901 BlueEFFICIENCY unit while retaining the same power output but with improved fuel economy and lower emissions.

Mercedes-Benz B Class B180 CDI

  1. September 2005 - W245 launch: OM640.940 2.0L diesel, 109bhp, 250Nm torque, Euro 4 emissions

  2. July 2005 - Diesel Particulate Filter becomes standard equipment from this date

  3. 2008

    W245 facelift: cosmetic updates only; engine range unchanged

  4. November 2011 - W246 launch: OM651.901 1.8L diesel BlueEFFICIENCY, 109bhp, 250Nm torque, Euro 5 emissions

  5. 2014

    W246 facelift: OM651.901 continues, revised styling and interior updates

Every engine fitted to the Mercedes-Benz B Class B180 CDI is covered below, with UK rebuilt pricing and known failure points.

Engine Codes & Pricing

Mercedes-Benz B Class B180 CDI Engine Codes Specifications & Replacement Cost

Find your exact engine code, specs and UK replacement cost guide.

OM640.940 — 2.0L Diesel (2005-2011) engine

OM640.940 — 2.0L Diesel (2005-2011)

Power Output
109bhp (80kW) at 4,200rpm
Torque
250Nm at 1,600-2,600rpm
Years Fitted
2005-2011 (W245 generation)
Displacement
1,991cc
Compression Ratio
18.0:1

Can’t find your exact engine code?

-> Get quotes for OM640.940 Mercedes-Benz B Class B180 CDI engine replacement

Common Problems

Mercedes-Benz B Class B180 CDI Engine Problems Repair Cost vs Replacement

The Mercedes-Benz B Class B180 CDI is broadly reliable, but both engine families - the OM640.940 in W245 cars and the OM651.901 in W246 models - have well-documented failure points. Timing chain tensioner issues dominate OM651 enquiries, while injector and turbo failures affect higher-mileage OM640 units. Every rebuilt engine supplied through EnginesMarket includes upgraded components designed to address the original failure point, plus a minimum 12-month unlimited mileage warranty.

Common failure points and repair options

Timing Chain Tensioner Failure

Affected
Mercedes-Benz B Class B180 CDI (OM651.901, 2011-2018, W246)
Typical failure mileage
60,000-100,000 miles
Root cause
The timing chain tensioner loses hydraulic pressure, allowing chain slack and guide rail fracture. On OM651 diesels, the chain is located at the rear of the engine (gearbox side), requiring gearbox removal for replacement. A rattling noise on cold start is the first warning sign.

Repair options

Repair tierDealer priceSpecialist price
Preventative - Timing Chain & Tensioner Replacement£1,600-£2,400£900-£1,400
Intermediate - Chain Failure With Valve Damage£3,500-£5,000£2,200-£3,200
Full Replacement - Rebuilt/Reconditioned Engine£6,000-£8,500£1,800-£2,800
Our recommendation
On a W246 B180 CDI, if you hear chain rattle on cold start but the engine still runs smoothly, a specialist preventative chain replacement (£900-£1,400) is excellent value. If the chain has already jumped and valves are bent, compare rebuilt engine prices - a specialist fitted unit at £1,800-£2,800 often costs less than a dealer head rebuild and delivers a fresh warranty.
-> Compare rebuilt OM651.901 Mercedes-Benz B Class B180 CDI engine prices

Injector Failure

Affected
Mercedes-Benz B Class B180 CDI (OM640.940, 2005-2011, W245)
Typical failure mileage
100,000-140,000 miles
Root cause
Injector coil pack failure, seal leakage or carbon buildup around the injector nozzle causes misfire, rough idle, excessive smoke and hard starting when hot. Injector failure can lead to bore wash, damaging piston rings and cylinder bores.

Repair options

Repair tierDealer priceSpecialist price
Minor - Single Injector Replacement£550-£800£350-£500
Intermediate - Full Injector Set Replacement£1,800-£2,500£1,100-£1,600
Full Replacement - Rebuilt Engine With Upgraded Injectors£5,500-£7,500£1,800-£2,800
Our recommendation
Single injector failure is common on OM640 engines beyond 100,000 miles. A specialist replacement at £350-£500 is straightforward. However, if you're experiencing hard start when hot plus misfire and smoke, multiple injectors are likely failing - a full set replacement at £1,100-£1,600 is more cost-effective than repeated single swaps. Only consider engine replacement if injector failure has caused bore wash or the engine has other major issues.
-> Get quotes for OM640.940 injector replacement and rebuilt engines for your B180 CDI

DPF & EGR Cooler Blockage

Affected
Mercedes-Benz B Class B180 CDI (OM640.940, 2005-2011; OM651.901, 2011-2018)
Typical failure mileage
70,000-110,000 miles (DPF); 60,000-90,000 miles (EGR cooler)
Root cause
On both OM640 and OM651 engines, DPF blockages are common in vehicles used for short trips or urban driving, where the filter cannot regenerate properly. Soot accumulates, triggering warning lights, reduced performance and increased fuel consumption. Early W245 OM640 cars without DPF (pre-July 2005) are less affected, but post-July 2005 cars and all W246 models have DPF systems.

Repair options

Repair tierDealer priceSpecialist price
Minor - EGR Cooler Replacement£900-£1,300£550-£850
Intermediate - DPF Clean & EGR Replacement£1,200-£1,800£700-£1,100
Full Replacement - Rebuilt Engine With New Emissions Components£6,000-£8,500£1,800-£2,800
Our recommendation
On a B180 CDI beyond 80,000 miles, regular motorway driving helps the DPF regenerate naturally - short-trip cars are most at risk. If your DPF is clogged but not melted, an off-car professional clean (£700-£1,100) restores function. If the car has been driven in limp mode for extended periods, the DPF and turbo may be beyond repair - at that stage, a rebuilt engine with new emissions components is the only reliable long-term solution.
-> Compare rebuilt OM640.940 & OM651.901 Mercedes-Benz B Class B180 CDI engine prices with DPF and EGR replacements

Don't Let Engine Failure Write Off Your Mercedes-Benz B Class B180 CDI

Engine failure doesn't have to mean the end of the road for your B180 CDI. Whether you're facing timing chain rattle on an OM651.901, injector failure on an OM640.940, or DPF blockages on either generation, EnginesMarket makes it simple to compare prices from trusted UK Mercedes-Benz B Class B180 CDI specialists. Every rebuilt engine includes upgraded components designed to address the original failure point - plus a minimum 12-month unlimited mileage warranty. Compare prices today, choose a vetted specialist, and get back on the road without the main dealer premium.

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FAQ

Mercedes-Benz B Class B180 CDI Engine ReplacementFrequently Asked Questions

Everything Mercedes-Benz B Class B180 CDI owners usually ask before choosing a rebuilt, reconditioned or used replacement engine.

Why Choose Us

Compare Mercedes-Benz B Class B180 CDI Engine Prices Today

Comparing quotes for your Mercedes-Benz B Class B180 CDI engine replacement is completely free and carries no obligation. Simply enter your registration above, tell us your engine code (OM640.940 or OM651.901), and receive tailored prices from trusted UK specialists who stock the right unit for your generation. Every rebuilt engine includes a minimum 12-month unlimited mileage warranty - compare today and get back on the road with confidence.

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