Problems And Reliability Issues Mercedes ML Generation 3 (W166)


When you say Daimler or Mercedes Benz, you’re thinking of premium cars, expensive cars with above-average design and high performance, which are highly valued by drivers, and that’s normal! After all, the two Daimler and Benz engineers were not the inventors of the first internal combustion engine in history!

From the start you should be aware that a premium, expensive car had much higher service prices and this is due to the complexity but also because the parts are much more expensive. The fact that they are machines that also innovate in terms of equipment can also mean a lower reliability.

That’s why we said today to make a reliability report for drivers who have such a car or are thinking of buying a used one.

Mercedes Benz ML (2011 – 2019) – Brief history

In 2006, the development of the next generation of the 3rd Class M began and lasted about 5 years under the code name W166. Production began in mid-2011 in the SUV version and took 5 Stars in the Euro NCAP tests. In 2015 Mercedes launches the coupe version of the car codenamed C292, the main changes being on the outside with technical aspects similar to the ML

The face-lift version of the SUV model is launched in 2016, and 3 years later the production stops at the end of 2019 with the appearance of the new model.

The car has several engines on gasoline, all starting from 3000 cubic cm upwards and on diesel – the favorite engine of the novel we find 2 engines:

3 liter Diesel (2,987 cc) 24V V6 single turbine (254 hp)
2 liter Diesel (2,143 cc) 16V I4 Bi-turbo (204 hp)

So what are the most common problems?

From the start we have to tell you that the car had several service recalls that the manufacturer solved. Here are just a few:

  • 2012 Mercedes-Benz W166 M-Class: the mat may interfere with acceleration
  • 2012 Mercedes-Benz W166 M-Class: Replacement Piezo Injector with Solenoid Technology
  • 2014 Mercedes-Benz W166 M-Class Diesel 2.1 L: oil spill
  • 2015 Mercedes-Benz Wi66 – Class: a short circuit could stop the wipers
  • 2015 Mercedes-Benz W166 M-Class: right rear seat belt, reassembled
  • 2015 – 2016 Mercedes-Benz W166 ML: front passenger airbag may not take off
  • 2012 – 2015 Mercedes-Benz W166 M-Class: Danger of fire due to contact with exhaust system oil

Be sure to check the chassis series to see if the car has had these problems resolved. Now let’s move on to the issues that drivers have reported.

Timing chain and tensioner wear

The problem is similar to the story of the N47 engine from BMW, Read here This is the 2.1 liter engine code engine OM651 being the most popular engine on this model in our country.

Exhaust chain wear and / or tensioner wear on high mileage engines. The problem is that the timing is mounted on the back of the engine, so servicing or changing is an expensive operation.

In general, the buzzing noise present immediately after starting the engine for 3-4 seconds is the first sign, and if this sound is permanently present, go to the car as soon as possible to change the distribution.

It would be advisable to replace the distribution between 220,000 km and 300,000 km depending on how the car was driven and the oil change intervals. Some drivers after the first 200,000 km changed only the stretcher and later after 300,000 changed the distribution completely.

Electrical problems

These problems were also reported by many drivers and the problems required repairs to the dealership

  • Premature battery failure
  • Electrical problems with on-board instrument lighting
  • Electrical malfunction of windows
  • Deadline warning sensor and lane departure issues
  • Parking sensor problems
  • Problems with signaling
  • Electric steering wheel adjustment problems

When you want to buy a car, check every electrical component, make sure it works because repairs can cost you a lot and there are few specialties to turn to.

Airmatic air suspension

In the classic version – that is, with springs, the car resists like a tank, no problem, maybe only the shock absorbers give way but somewhere after 150,000 km, anyway the shock absorbers can be considered a consumable car. But the air cushion suspension is more demanding and quite expensive!

When these air springs fail, they are replaced, they are not repaired and the experts recommend that you do it in pairs! The prices are very high so check if they have been changed before buying the car.

To prevent damage to the airbags, it is recommended that you wash the cylinders thoroughly every time, so that no dirt remains, especially if you have traveled a section of Off Road.

Other problems reported by some drivers

  • Oil flowing through the oil bath cap
  • Excessively worn arms and bushes
  • Engine mounts
  • The gearbox is jerky
  • Catalyst issues
  • Summary and purchasing tips

The Mercedes ML W166 is a car with many options, so it’s more likely that something will go wrong – it’s normal. The ML does not enter any top of reliability but it is not a car to run away from either. Even if the 2.1 Liter engine has some problems, it is quite well known in our country, there are enough parts to repair it at the same time.

The best option is to choose a model serviced on time or even ahead of time with a complete history, with quality consumables, without incidents that required major repairs and necessarily with spring suspension!

What problems did you encounter with this model and on what engine?


carvertical VINCheck the car on CAR-VERTICAL before purchase so as not to wake up with a double number of Km or major accidents!

Read also –  Defects that may occur in the Opel Astra J – Causes and Costs


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