Air suspension (Airmatic)
usually 100,000–200,000 km · Medium risk
Signs: Car sits low, compressor runs long
Fix: Replace strut / compressor
€700–2,200
Common faults, service intervals and costs
Mercedes-Benz GL / GLS (X166)
2012–2019
2
engines covered
8
known faults
4,154
roadworthiness tests in the statistics
Enter your VIN and mileage and get a plan built for your exact engine and gearbox.
The Mercedes-Benz GL / GLS (X166) was built from 2012 to 2019.
For this generation we cover 2 engines and 8 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 (6.3 %), lights, wipers and visibility (3.0 %), brakes (2.4 %). It fails more often than an average car of the same age and mileage on: body and corrosion. It fails less often than average on: brakes, suspension, lights, wipers and visibility.
Engines
| Engine | Fuel | Timing drive | Oil |
|---|---|---|---|
| 3.0 CDI V6 (Mercedes OM642) | Diesel | Chain | 5W-30 · MB 229.51 · ~8.0 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 |
Faults typical of this model
Faults by engine
3.0 CDI V6 (Mercedes OM642)
Oil cooler seals (engine valley)
usually 120,000–220,000 km · High risk
Signs: Oil leak at the back of the engine / bellhousing
Fix: Reseal the oil cooler (intake off)
€1,000–2,000
Intake swirl flaps / actuator
usually 120,000–220,000 km · Medium risk
Signs: Engine light, limp mode
Fix: Replace manifold or actuator
€600–1,500
EGR / DPF
usually 150,000–250,000 km · Medium risk
Signs: Limp mode
Fix: Clean or replace
€400–1,800
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
Gearboxes
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 3.0 CDI V6 (Mercedes OM642) engine. Other engines differ in oil, timing drive and some filters; the app gives the exact plan.
| Item | Interval | Typical price |
|---|---|---|
| DPF health check (soot / ash load)Emissions | every 20,000 km | €0–60 |
| Transfer case / rear differential oilTransmission | every 80,000 km | €60–160 |
| 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 |
| Automatic transmission fluidTransmission | every 90,000 km | €200–450 |
| 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 |
| 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: 4,154 tests.
| thousand km | 50–100 | 100–150 | 150–200 |
|---|---|---|---|
| Brakes | 2.4 % | 2.4 % | 1.7 % |
| Suspension | 0.7 % | 0.6 % | 1.8 % |
| Steering | 0.0 % | 0.3 % | 0.3 % |
| Tyres and wheels | 6.3 % | 8.7 % | 8.6 % |
| Lights, wipers and visibility | 3.0 % | 4.1 % | 5.7 % |
| Body and corrosion | 1.4 % | 1.8 % | 2.5 % |
| Exhaust, emissions and leaks | 1.3 % | 2.5 % | 3.0 % |
Most common engine versions in the EU
New cars of this generation registered in the EU, Iceland and Norway 2010–2025: 22,593, of which 16 in Croatia. The share shows how common each version is.
| Version | Share | Years | CO₂ | Fuel use |
|---|---|---|---|---|
| 3.0 CDI V6 (Mercedes OM642)3.0 (2,987 cm³) · 190 kW (258 hp) · Diesel | 62.0 % | 2013–2019 | 230 g/km | — |
| 3.0 CDI V6 (Mercedes OM642)3.0 (2,987 cm³) · Diesel | 20.7 % | 2013–2018 | 225 g/km | — |
| 3.0 / 3.5 V6 petrol (Mercedes M276)3.0 (2,996 cm³) · 245 kW (333 hp) · Petrol | 4.7 % | 2014–2018 | 246 g/km | — |
| 4.7 Petrol4.7 (4,663 cm³) · 320 kW (435 hp) · Petrol | 3.8 % | 2013–2017 | 264 g/km | — |
| 4.7 Petrol4.7 (4,663 cm³) · 335 kW (455 hp) · Petrol | 3.5 % | 2015–2018 | 283 g/km | — |
| 5.5 Petrol5.5 (5,461 cm³) · 410 kW (557 hp) · Petrol | 1.9 % | 2013–2017 | 288 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.
Owner complaints in the US
Which systems owners reported to the US agency NHTSA and at what mileage. Complaints are not confirmed faults and some relate to recalls. Sample: 158 complaints.
Common questions
Does the Mercedes-Benz GL / GLS (X166) have a timing chain or a timing belt?
3.0 CDI V6 (Mercedes OM642): chain; 3.0 / 3.5 V6 petrol (Mercedes M276): chain.
What are the known problems with the Mercedes-Benz GL / GLS (X166)?
The faults with the highest risk: oil cooler seals (engine valley) (120,000–220,000 km, €1,000–2,000); timing chain tensioners / oil check valves — cold-start rattle (60,000–160,000 km, €400–2,500); air suspension (Airmatic) (100,000–200,000 km, €700–2,200); EGR / DPF (150,000–250,000 km, €400–1,800). The full list by engine is on this page.
What does the Mercedes-Benz GL / GLS (X166) most often fail its roadworthiness test on?
In UK roadworthiness tests in 2024, at 50–100 thousand km this model most often failed on: tyres and wheels (6.3 %), lights, wipers and visibility (3.0 %), brakes (2.4 %). It fails more often than an average car of the same age and mileage on: body and corrosion. It fails less often than average on: brakes, suspension, lights, wipers and visibility.
What should you check when buying a used Mercedes-Benz GL / GLS (X166)?
Before you buy, ask an authorised dealer to check by VIN whether the car has any open recalls. On the test drive, watch for these signs: oil leak at the back of the engine / bellhousing; rattle for a few seconds after a cold start. The full checklist is in the guide to buying a used car.
Models with the same engines
These models share engines with this car, so they share some of its faults too.
Mercedes-Benz C-Class (W204) 2007–2014Mercedes-Benz E-Class (W212) 2009–2016Mercedes-Benz E-Class (W213) 2016–2023Mercedes-Benz ML / GLE (W166) 2011–2019Mercedes-Benz Sprinter (906) 2006–2018Mercedes-Benz Sprinter (907 / 910) 2018–Mercedes-Benz Vito (W639) 2003–2014Mercedes-Benz GLK (X204) 2008–2015
Other Mercedes-Benz models
Mercedes-Benz A-Class (W176) 2012–2018Mercedes-Benz Citan (W415) 2012–2021Mercedes-Benz SL (R231) 2012–2020Mercedes-Benz B-Class (W246) 2011–2018Mercedes-Benz CLA (C117) 2013–2019Mercedes-Benz CLS (C218) 2011–2018Mercedes-Benz GLA (X156) 2013–2020Mercedes-Benz S-Class (W222) 2013–2020Mercedes-Benz SLK / SLC (R172) 2011–2020Mercedes-Benz C-Class (W205) 2014–2021
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. 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.
Updated 08/10/2026