Diesel · 2014–2021
Enter your VIN and mileage and get a plan built for your exact engine and gearbox.
All about the Mercedes-Benz C-Class (W205)All about the 1.6 dCi (Renault-Nissan R9M, also Mercedes OM626) engine
The 1.6 dCi (Renault-Nissan R9M, also Mercedes OM626) engine was fitted to the Mercedes-Benz C-Class (W205) (2014–2021). In the EU that is 11.3 % of all new cars of this generation.
Versions: 1.6 136 hp, 1.6 116 hp, 1.6 160 hp.
The most expensive known risk is EGR cooler or EGR pipe cracks, exhaust smell in the cabin (mainly twin-turbo): it usually appears at 60,000–200,000 km and costs €400–2,000 to fix.
✓ The faults of this engine were checked against sources (10/2026). Each item has at least two independent sources or an official recall or parts-maker technical note.
Signs: Loss of power, limp mode, underboost or overboost codes (P0299 / P0234), whistling
Fix: Check boost hoses, the vacuum or electric actuator and the pressure sensor first; free or replace the sticking vanes / turbo if the geometry is seized
Signs: Jerky acceleration, power loss, engine light with EGR codes; worse with short town trips
Fix: Check EGR position in live data; clean the valve and intake or replace the valve if it sticks
Signs: Smell of exhaust in the cabin or engine bay, ticking or hissing leak, sometimes coolant loss
Fix: Find the leak with the engine running; replace the cracked EGR cooler or pipe and check with the dealer by VIN for any campaign on the EGR pipe
Signs: DPF warning, frequent or interrupted regenerations, limp mode; mostly cars used for short trips
Fix: Check the differential pressure sensor and EGR first, then forced regeneration, cleaning or replacement; use low-ash RN0720 oil
Signs: Hard starting, rough idle, smoke, misfire, injector correction or rail pressure fault codes
Fix: Read injector corrections and do a return-flow test; replace the faulty injector(s) with new seals and code them to the ECU
Signs: Metallic rattle for a few seconds after a cold start, camshaft/crankshaft correlation codes; a jumped chain damages the valves
Fix: Keep to the oil spec and do not stretch oil intervals; at the first rattle replace the chain kit (chain, guides, tensioner, sprockets)
Signs: Oil wetting at the front of the engine or around the filter housing, drops under the car
Fix: Find the source; reseal the timing cover or replace the oil filter housing gasket
Signs: Usually none; the NOx trap loses efficiency through sulphur build-up, sometimes poorer performance
Fix: Have a Renault dealer check by VIN that the free ECU reprogramming was done
Signs: No warning; after a hard side impact (e.g. hitting a kerb) the steering gear can jam.
Fix: Check the VIN; the dealer inspects the steering and replaces the electric steering gear free of charge.
Signs: No warning; road salt corrodes the bolts and power steering assistance can suddenly fail, mostly when parking.
Fix: Check the VIN; the dealer replaces the bolts with steel ones free of charge.
Signs: Airbag warning light or message; with a damaged clockspring, static discharge can deploy the driver airbag without a crash.
Fix: Check the VIN; the dealer adds a proper earth to the steering column free of charge.
Signs: Car sinks on one corner overnight, compressor runs often, suspension fault message.
Fix: Find the leak with leak spray or diagnostics and replace the leaking air strut or line before the compressor burns out.
Signs: Slipping, high bite point
Fix: Replace clutch kit
Signs: Rattle at idle, vibration pulling away
Fix: Replace with clutch
Signs: Holds a gear too long then shifts hard, sticks in gear or limp mode, converter lock-up stops working; codes 0717 / 0718 / 0722 / 2201
Fix: Confirm with Mercedes-level diagnostics; replace or rebuild the conductor plate (with the valve body on early VGS1 units), change the fluid with the correct MB spec and code / adapt the unit
Signs: Harsh shifts when warm, drops from D to N at stops, starts in 3rd, reverse will not engage, 'F' on the dash; codes P073E00, P07B700
Fix: Read the codes and fluid condition; repair / rebuild the mechatronic (pressure sensors) or replace it, then change the fluid and run the adaptations
Typical routine maintenance cost for 100,000 km: €2,400–5,750. Sum of the services and wear parts in the plan above (about 15,000 km a year, independent workshop), without faults.
Intervals and typical prices for the Mercedes-Benz C-Class (W205) with the 1.6 dCi (Renault-Nissan R9M, also Mercedes OM626) engine. The app gives the exact plan for your mileage.
| Item | Interval | Typical price |
|---|---|---|
| DPF health check (soot / ash load)Emissions | every 20,000 km | €0–60 |
| Engine oil + oil filterEngine | every 15,000 km or every 12 months | €70–150 |
| Cabin (pollen) filterClimate | every 15,000 km or every 12 months | €15–40 |
| Brake fluidBrakes | every 24 months | €50–95 |
| A/C service (regas + desiccant)Climate | every 24 months | €70–150 |
| Air filterEngine | every 30,000 km or every 24 months | €15–45 |
| Fuel filterFuel | every 30,000 km or every 24 months | €40–110 |
| Glow plugsEngine | every 100,000 km | €120–300 |
| Auxiliary (serpentine) beltEngine | every 120,000 km | €70–180 |
| Coolant replacementCooling | every 150,000 km or every 96 months | €70–150 |
| Timing chain inspection (listen on cold start)Engine | every 150,000 km | €0–120 |
| Manual gearbox oilTransmission | every 150,000 km | €60–130 |
| Front brake padsBrakes | usually at 30,000–60,000 km | €60–150 |
| Front brake discs + padsBrakes | usually at 60,000–120,000 km | €150–320 |
| Rear brake padsBrakes | usually at 50,000–90,000 km | €50–130 |
| Tyres (set of 4)Wheels | usually at 40,000–60,000 km | €320–700 |
| Wiper bladesBody | checked at service | €20–50 |
| 12V batteryElectrical | checked at service | €100–220 |
| Version | Share | Years | CO₂ | Fuel use |
|---|---|---|---|---|
| 1.6 Diesel1,598 cm³ · 100 kW (136 hp) | 3.6 % | 2015–2020 | 110 g/km | — |
| 1.6 Diesel1,598 cm³ · 85 kW (116 hp) | 2.8 % | 2015–2019 | 111 g/km | — |
| 1.6 Diesel1,597 cm³ · 118 kW (160 hp) | 2.8 % | 2018–2020 | 139 g/km | — |
Source: European Environment Agency (EEA), monitoring of CO₂ emissions from new passenger cars, CC BY 4.0. CO₂ and fuel use are official type-approval values (WLTP from 2021), not real-world consumption.
Recalls the manufacturer published in the United Kingdom for this model (115). The same recalls usually apply across Europe. Ask an authorised dealer to check by VIN whether your car is affected and whether the work has been done.
The faults with the highest risk: EGR cooler or EGR pipe cracks, exhaust smell in the cabin (mainly twin-turbo) (60,000–200,000 km, €400–2,000); timing chain stretch (rattle on cold start) (100,000–200,000 km, €1,000–2,000); airmatic air suspension leaks (strut, lines, compressor) (80,000–250,000 km, €500–2,000); DPF clogging, failed regenerations (80,000–200,000 km, €150–1,800).
Chain.
5W-30 / 0W-30 · Renault RN0720 · ~5.5 L · every 15,000 km.
2.1 CDI (Mercedes OM651)1.6 / 2.0 petrol (Mercedes M274)1.5 / 2.0 petrol (Mercedes M260 / M264)2.0 d (Mercedes OM654)
Nissan Qashqai (J11) 2013–2021Renault Kadjar 2015–2022Renault Trafic III 2014–Opel Vivaro B 2014–2019Nissan X-Trail (T32) 2013–2022Renault Scénic III 2009–2016Renault Talisman 2015–2022Renault Scénic IV 2016–2022Renault Koleos II 2016–Renault Espace V 2015–2023
Main sources for the faults of this engine:
Faults, intervals and prices are indicative and collected from public sources and owner experience; always rely on the service book and a qualified workshop. Test statistics: DVSA – Anonymised MOT tests and results, Open Government Licence v3.0. Dutch tests: RDW Open Data (CC0). Engine versions: EEA, monitoring of CO₂ emissions from new passenger cars (CC BY 4.0, DG CLIMA). Owner complaints: NHTSA ODI (public domain). Recalls: DVSA Vehicle Safety Branch Recalls Database, OGL v3.0. Brand and model names are trademarks of their owners and are used only to describe the vehicles. How we check the data →
Updated 29/10/2026