Camshaft adjuster magnet oil leak
usually 80,000–160,000 km · Medium risk
Signs: Oil in the wiring plug — can reach the ECU
Fix: Replace magnet, check the harness
€150–600
Common faults, service intervals and costs
Mercedes-Benz SLK / SLC (R172)
2011–2020
4
engines covered
10
known faults
32,297
roadworthiness tests in the statistics
Enter your VIN and mileage and get a plan built for your exact engine and gearbox.
The Mercedes-Benz SLK / SLC (R172) was built from 2011 to 2020.
For this generation we cover 4 engines and 10 known faults, each with the mileage range where it usually appears.
The most expensive known risk is Timing chain tensioners / oil check valves — cold-start rattle: it usually appears at 60,000–160,000 km and costs €400–2,500 to fix.
In UK roadworthiness tests in 2024, at 50–100 thousand km this model most often failed on: tyres and wheels (8.0 %), suspension (7.8 %), lights, wipers and visibility (4.2 %). It fails more often than an average car of the same age and mileage on: tyres and wheels. It fails less often than average on: brakes, lights, wipers and visibility, exhaust, emissions and leaks.
Engines
| Engine | Fuel | Timing drive | Oil |
|---|---|---|---|
| 1.6 / 1.8 Kompressor / CGI (Mercedes M271) | Petrol | Chain | 5W-30 / 5W-40 · MB 229.5 · ~5.5 L · every 15,000 km |
| 1.6 / 2.0 petrol (Mercedes M274) | Petrol | Chain | 5W-30 · MB 229.5 · ~5.8 L · every 15,000 km |
| 3.0 / 3.5 V6 petrol (Mercedes M276) | Petrol | Chain | 5W-30 / 0W-40 · MB 229.5 · ~6.5 L · every 15,000 km |
| 2.1 CDI (Mercedes OM651) | Diesel | Chain | 5W-30 · MB 229.51 / 229.52 · ~6.5 L · every 15,000 km |
Faults by engine
1.6 / 1.8 Kompressor / CGI (Mercedes M271)
Crankcase breather hoses
usually 100,000–200,000 km · Wear part
Signs: Oil leaks, whistle
Fix: Replace hoses
€100–300
1.6 / 2.0 petrol (Mercedes M274)
Camshaft adjuster solenoid oil leak
usually 60,000–140,000 km · Medium risk
Signs: Oil in the wiring plug, check-engine light
Fix: Replace solenoids, check the harness
€200–500
Timing chain stretch
usually 150,000–250,000 km · High risk
Signs: Cold-start rattle
Fix: Replace chain and adjusters
€1,500–3,000
3.0 / 3.5 V6 petrol (Mercedes M276)
Timing chain tensioners / oil check valves — cold-start rattle
usually 60,000–160,000 km · Medium risk
Signs: Rattle for a few seconds after a cold start
Fix: Fit the updated tensioners and check valves; replace the chain if it has stretched
€400–2,500
Camshaft adjuster solenoid oil leak
usually 60,000–140,000 km · Medium risk
Signs: Oil in the wiring plug, check-engine light
Fix: Replace solenoids, check the harness
€200–500
Thermostat / coolant leaks
usually 100,000–200,000 km · Wear part
Signs: Slow warm-up, coolant loss
Fix: Replace thermostat
€150–400
2.1 CDI (Mercedes OM651)
Piezo injectors (2009–2011)
usually 60,000–140,000 km · High risk
Signs: Rough running, knocking, no-start
Fix: Replace injectors (check campaign)
€1,000–2,500
Timing chain stretch
usually 200,000–280,000 km · Medium risk
Signs: Correlation codes, rattle
Fix: Replace chain
€1,200–2,200
EGR / DPF
usually 150,000–220,000 km · Medium risk
Signs: Limp mode, DPF light
Fix: Clean or replace
€300–1,500
Gearboxes
Manual
Clutch wear
usually 120,000–200,000 km · Medium risk
Signs: Slipping, high bite point
Fix: Replace clutch kit
€500–900
5G / 7G / 9G-Tronic
Conductor plate / speed sensor (5G / 7G-Tronic)
usually 100,000–220,000 km · Medium risk
Signs: Stuck in gear, limp mode, harsh shifts
Fix: Replace the conductor plate; fluid every 60–100,000 km
€500–1,500
Scheduled service
Intervals and typical prices for the 1.6 / 1.8 Kompressor / CGI (Mercedes M271) engine. Other engines differ in oil, timing drive and some filters; the app gives the exact plan.
| Item | Interval | Typical price |
|---|---|---|
| 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 |
| Spark plugsIgnition | every 60,000 km or every 48 months | €50–160 |
| 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 |
Roadworthiness tests by mileage
Share of tests in the United Kingdom (DVSA MOT, 2024) that this model failed because of each system. Bold red means more often and green less often than an average car of the same age and mileage. Sample: 32,297 tests.
| thousand km | 0–50 | 50–100 | 100–150 | 150–200 |
|---|---|---|---|---|
| Brakes | 1.2 % | 3.1 % | 5.5 % | 6.9 % |
| Suspension | 2.1 % | 7.8 % | 13.1 % | 18.5 % |
| Steering | 0.0 % | 0.1 % | 0.2 % | 0.1 % |
| Tyres and wheels | 4.6 % | 8.0 % | 10.1 % | 11.2 % |
| Lights, wipers and visibility | 2.2 % | 4.2 % | 6.2 % | 9.1 % |
| Body and corrosion | 0.1 % | 0.3 % | 0.6 % | 0.8 % |
| Exhaust, emissions and leaks | 0.8 % | 1.0 % | 1.4 % | 2.2 % |
Sources and notes
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. 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.
Updated 07/10/2026