Recalls: Mercedes-Benz W166 M-Class
Overview
Manufacturers, or importers, issue recalls for defects or faults which have the potential to cause injury. Generally, manufacturers will inform the original buyers if their vehicle is subject to a recall and of the steps required to remedy the defect or fault. Please note that the recalls below (if any) are for Australian-delivered vehicles only. Furthermore, the number of recalls should not be taken as an indication of a model’s reliability or its safety more generally.
Recalls: Mercedes-Benz W166 M-Class
2012 Mercedes-Benz W166 M-Class: floor mat could interfere with accelerator
In December 2012, a recall was issued for Mercedes-Benz W166 M-Class vehicles that were manufactured from March 2012 to August 2012. In isolated cases, the accelerator pedal may contact the floor mat – this could interfere with pedal operation and result in unexpected high vehicle speeds; it may also be difficult to stop or slow the vehicle (PRA 2012/13412).
2014 Mercedes-Benz W166 M-Class Diesel: oil leak
In January 2015, a recall was issued for Mercedes-Benz vehicles with the OM651 turbo-diesel engine that were available for sale during 2014. In these vehicles, the seal ring between the timing chain tensioner and the engine may leak oil – this could result in a hazard for other road users and, in extreme cases, a fire risk (PRA 2015/14509).
2015 Mercedes-Benz W166 M-Class: short circuit could stop wipers
In November 2015, a recall was issued for Mercedes-Benz W166 ML vehicles that were available for sale from 1 February 2015 to 30 October 2015. In these vehicles, the battery cable may be incorrectly positioned and may contact the wiper arm – if this occurred, the resulting short circuit may prevent the wipers from working. Non-functioning wipers could impair visibility, posing a hazard to the driver and other road users (PRA 2015/15053).
2015 Mercedes-Benz W166 M-Class: right rear seat belt
In July 2016, a recall was issued for Mercedes-Benz W166 M-Class vehicles that were available for sale from 1 May 2015 to 31 July 2015. In these vehicles, the lower mount for the right rear seatbelt may not have been fitted according to specification. In the event of a high impact collision, the seatbelt mounting could fail and increase the risk of injury to passengers (PRA 2016/15555).
2015-16 Mercedes-Benz W166 ML: front passenger airbag may not deploy
In December 2016, a recall was issued for Mercedes-Benz W166 ML vehicles that were available for sale in Australia from 1 June 2015 to 31 March 2016. In these vehicles, incorrect software coding within the front passenger seat occupancy recognition control unit could prevent the airbag system from detecting an occupant in the front passenger seat. In the event of a collision, the front airbag may therefore not deploy and this would increase the risk of injury (PRA 2016/15819).
2012-15 Mercedes-Benz W166 M-Class: fire hazard from oil contacting exhaust system
In September 2018, a recall was issued for Mercedes-Benz W166 M-Class vehicles that were available for sale in Australia from 1 February 2012. Under ‘dynamic operating conditions’, oil foam could develop in the system’s oil reservoir if oil was below the minimum level. This could cause oil to escape via the ventilation bores in the cap of the reservoir and escaping oil could spray onto hot components parts of the exhaust system and cause a fire. For the VINs of the recalled vehicles, please see PRA 2018/16986.
2012-15 Mercedes-Benz W166 M-Class: water could enter fuel pump control unit
In February 2023, recall campaign RC311 was issued for 2012-15 Mercedes-Benz W166 M-Class vehicles. Due to a manufacturing defect, water could come into contact with the fuel pump control unit – this could impair the fuel supply to the engine and result in a loss of power while driving. A loss of power while driving could increase the risk of a collision and injury to vehicle occupants, other road users and bystanders. For the VINs of the recalled vehicles, please see REC-005622.
Problems and faults: Mercedes-Benz W166 M-Class
Overview
This section identifies potential problems, causes and fixes based on the experiences of owners and repairers, online sources and technical service bulletins. This information is provided solely for reference purposes and AustralianCar.Reviews recommends that only properly qualified persons carry out repairs or modifications. Furthermore, the number of items below should not be taken as an indicator of a model’s reliability or the frequency with which they may occur.
To report a problem or fault to the AustralianCar.Reviews team, please use the Contact Us form. Note that AustralianCar.Reviews does not offer advice on automotive problems or disputes; such enquiries will not receive a reply. For vehicles purchased from dealers after 1 January 2011, please see our Australian Consumer Law fact sheet.
Mercedes-Benz W166 ML 250 BlueTec: OM651 timing chain and tensioner wear
For the Mercedes-Benz W166 ML 250 BlueTec’s OM651 turbo-diesel engine, there have been reports of wear of the simplex timing chain and/or chain tensioner at higher mileages. Since the chain is installed on the transmission side of the engine, access is restricted and replacement is expensive.
2013 model year Mercedes-Benz W166 ML 500: oil supply to cylinder head
In February 2013, Service Campaign Bulletin No. 2013010001 was issued for 2013 model year Mercedes-Benz W216 ML 500 vehicles that had 4.7-litre biturbo M278 V8 engines. During installation at the factory, the check valve of the left and right secondary chain tensioners may have been pressed too deep into the cylinder heads and this could compromise oil supply into the cylinder head. As part of this service campaign, the check valve of the left and right secondary chain tensioners was to be removed.
Mercedes-Benz W166 ML 350 and ML 500: engine rattle noise after start-up
In December 2015, Mercedes-Benz issued Service Bulletin LI05.10-P-056435 Version 10 for Mercedes-Benz W166 ML 350 and ML 500 vehicles that had the following engines:
- M2768 (ML 350 and ML 400): up to engine 2768xx 30 001281;
- M2769 (ML 350 and ML 400): up to engine 2769xx 30 406603; and
- M278 (ML 500): up to engine 2789xx 30 191843.
According to the Service Bulletin, the driver may hear a rattling noise after start-up – from the engine compartment – that lasts for several seconds. This noise was attributed to a lack of oil pressure in the secondary chain tensioners, though Mercedes-Benz claimed that no consequential damage was to be expected.
To fix, the secondary chain tensioners (left and right) were to be replaced and a check valve was to be installed in the oil supply bore of each secondary chain tensioner in the cylinder head (left and right).
