C 220 d OM651

The four-cylinder diesel that carried Mercedes for a decade. Durable bottom end; the money is in the injectors, and early piezo units are the reason some of these cars are cheap.

Overview

The C 220 d is the OM651 diesel version of the Mercedes-Benz C-Class wagon (S205), sold 2014–2018 with 170 PS and manual or automatic. Manageable at level 2. This later OM651 sits after the injector and chain revisions, so the emissions hardware is the main cost. 3 failure modes are recorded against its engine, gearbox, chassis and shared components. Prices on this page are illustrative placeholders rather than a sourced market sample. See the methodology for how the bands are derived.

Power170 PS
Torque400 Nm
Years2014–2018
Fueldiesel
DriveRWD / 4MATIC
EnginesOM651
Biggest risks

Ranked by probability × repair cost. 3 recorded in total.

82Dependable
  1. DPF clogging and forced regeneration€250€1,800partly checkable
  2. 7G-Tronic conductor plate and 13-pin connector leak (722.9)€400€900partly checkable
  3. EGR cooler leak€400€1,000partly checkable

Risk level −11 · Likely spend vs price −7 · all issues →

System by system9 systems reviewed · 7 with no recurring fault reported
Engine✓ clearNo recurring fault reported for this system on this engine.
Fuel system✓ clearNo recurring fault reported for this system on this engine.
Intake & air✓ clearNo recurring fault reported for this system on this engine.
Cooling✓ clearNo recurring fault reported for this system on this engine.
Emissions⚠ attentionDPF clogging and forced regeneration, €250–€1,800.+1 more in this system
Electrics✓ clearNo recurring fault reported for this system on this engine.
Suspension & brakes✓ clearNo recurring fault reported for this system on this engine.
Body & interior✓ clearNo recurring fault reported for this system on this engine.

Pre-facelift or facelift, this engine spans both

The same badge either side of the changeover. Bands are split at the facelift year from the generation record.

PhaseYearsLowAverageHighGood buyWhat differs
pre Pre-facelift2014–2017€11,450€16,100€22,900€13,800The specification the car launched with.
LCI Facelift (LCI)2018€12,450€17,550€24,950€15,000OM654 and M264 engines replaced OM651 and M274; Revised lights and bumpers; Digital instruments available

Known issues, ranked by expected cost

Faults recorded against this engine, its components and its chassis, ranked by likelihood × repair cost. Costs are indicative ranges with a stated labour basis.

Warning light, limp mode, oil level rising above the maximum mark from fuel dilution. The filter needs sustained hot running to regenerate. A car used for short urban trips never completes a regeneration cycle.
Check: Read the DPF soot load and the distance since the last regeneration on a scan tool, and check the engine oil level and smell it for diesel. Ask what the car was used for. A short-trip city diesel is the wrong car regardless of mileage.
EmissionscommonPartly detectableevidence: documented120250k km
7G-Tronic conductor plate and 13-pin connector leak (722.9)Mercedes 7G-Tronic seven-speed automatic (722.9)€400–€900
Harsh, delayed or jerky shifts, holding a gear then banging the next in, and limp mode, often with speed-sensor or gear-ratio fault codes. The speed sensors in the conductor plate (mechatronic) fail, and/or the external 13-pin connector leaks fluid that wicks up the wiring into the control unit. Early units are the most affected.
Check: Test-drive through every gear cold and warm. Scan the transmission, and pull the external 13-pin plug to check for fluid on the pins.
TransmissioncommonPartly detectableevidence: documented120220k km
EGR cooler leakEGR cooler€400–€1,000
Coolant loss with no visible external leak, white smoke, sweet smell. The EGR cooler cracks internally and leaks coolant into the intake. BMW recalled affected diesels over a fire risk from glycol deposits igniting.
Check: Check coolant level and look for unexplained top-ups in the service history. Verify the recall was carried out. It's free and searchable by VIN.
EmissionsoccasionalPartly detectableevidence: manufacturer120250k km

Ranked by probability × repair cost, not by how loudly a failure is discussed. Inherited from the engine, gearbox, chassis and shared components, each written once.

Pre-purchase inspection

The same issue records, reordered into the sequence you can actually check them in: cold start, static, drive, paperwork.

3 checks · saved in this browser ·

1On the driveInclude low-speed manoeuvring, not just an open road.

2PaperworkOn these cars the folder is most of the value.

3OBD scanMandatory. A seller who refuses a scan has answered the question.

Mileage and servicing

What the odometer does and doesn't tell you here, plus the service items whose neglect causes the expensive failures above.

These cover motorway distance happily and a 200,000 km car with a full record is a sound buy. Short-trip history is what hurts them, so ask about the daily run.

Service itemIntervalCost
Engine oil and filter
Low-ash oil protects the filter, and the chain still likes regular changes.
15,000 km or annually€140–210
Gearbox oil and filter
Both automatics last longer with fresh oil than the schedule implies.
every 60,000–100,000 km€300–450

What to pay

What this engine sells for, against the median of every engine in the chassis. All figures are illustrative placeholders. See the basis chips.

Enter an asking price to get a verdict against this variant's band: cheap, fair, good buy or overpriced.

United States vs Europe

1 EUR = 1.08 USD ·
🇪🇺 Europe · EUR€13,800band €11,450€24,950
🇺🇸 United StatesNot soldC 220 d OM651 was never a US-market car
What that meansNo US band exists to compare. Any car you find there's a private import, parts and specialist knowledge are thinner, and the price says more about import cost than about the market.

US figures are the EU band converted at a stated rate. No US market differential is modelled: we hold no sourced US asking prices, and inventing one would be worse than saying so. What the comparison does show for real is availability. Most of this range was never sold in the US.

  • ModelMercedes-Benz C-Class C 220 d
  • ChassisS205
  • EngineOM651
  • Years2014–2018
  • MarketCentral EU
  • Windowrolling 12 months to 2026-07
€15k€20k€25kS205 median, all 2 engines €16,350Pre-faceliftPre-facelift: low €11,450, good buy €13,800, average €16,100, high €22,900€16,100€11,450€22,900€13,800Facelift (LCI)Facelift (LCI): low €12,450, good buy €15,000, average €17,550, high €24,950€17,550€12,450€24,950€15,000
Good buy at or under the marker · Median asking price · bar spans the 10th to 90th percentile · dashed line is the s205 median, all 2 engines

Good buy isn't the same as cheapest. The good-buy figure assumes the known failure items are either done with receipts or verifiably not yet due. Full breakdown by facelift phase →

Buyer notes

Our judgement, kept separate from the records it's built on.

Our read, not a record
The OM651 had a difficult start in the W204 and W212, and by the time it reached this car the injectors and the timing chain had both been revised. What's left is an economical, torquey diesel that suits the car's refinement. Check the particulate filter and the AdBlue system on later cars, since both throw warnings when neglected. So confirm the infotainment and driver-assistance systems work properly, because repairing modules on a car this complex is where the money goes.

Everything above this line comes from the issue and specification records. This paragraph is our judgement on top of them. See how we reach it.

Full specification

Manufacturer figures for this engine and body, as recorded in the variant and engine data.

Engine codeOM651 2.1 CDI
ConfigurationI4, turbocharged · 2143 cc
Fuel / injectiondiesel · common rail
Model years2014–2018
Facelift phaseSold either side of the 2018 facelift, 2014–2017 pre, 2018 LCI
Power / torque170 PS · 400 Nm
Transmissions6-speed manual · 7-speed automatic (7G-Tronic) · 9-speed automatic (9G-Tronic)
Gearbox familiesMercedes 7G-Tronic seven-speed automatic (722.9) · Mercedes 9G-Tronic nine-speed automatic (725.0)
DrivetrainRWD · 4MATIC
Economy (real-world)4.3–5.5 l/100 km mixed
MarketsEU