Recalls: Mercedes-Benz R172 SLK-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 R172 SLK-Class
Mercedes-Benz R172 SLK-Class: crack in fuel filter housing
In April 2013, a recall was issued for Mercedes-Benz R172 SLK-Class vehicles due to a potential crack in the fuel filter housing – this could result in a fuel leak and potential fire hazard (PRA 2013/13553).
2014 Mercedes-Benz R172 SLK-Class: passenger airbag module could break free
In August 2014, a recall was issued for Mercedes-Benz R172 SLK-Class vehicles that were available for sale from 1 March 2014 to 30 May 2014. In the event of an accident which may result in the deployment of the front passenger side dash-mounted airbag, small pieces of the airbag module may break free – these may cause injury to the vehicle occupants (PRA 2014/14242).
2015 Mercedes-Benz R172 SLK-Class: vehicle may not start and could roll away
In May 2016, a recall was issued for fifteen (15) Mercedes-Benz R172 SLK vehicles that were available for sale from 4 February 2015 to 28 September 2015. In the event of a failure of the main battery, the electronic ignition lock would not be supplied with power by the backup battery. If the engine stopped during use, the electric parking brake and the transmission position ‘P’ could not be activated. As such, the vehicle could not be restarted and securing the vehicle against rolling would only be possible by operating the brake pedal, thereby posing an accident hazard to the driver and other road users (PRA 2016/15352).
2016 Mercedes-Benz R172 SLK-Class: incorrect nuts on rear axle tie rods
In June 2016, a recall was issued for Mercedes-Benz R172 SLK vehicles that were available for sale from 1 January 2016 to 30 March 2016. In these vehicles, incorrectly sized nuts may have been fitted to the tie rods on the rear axle. If these nuts were to come loose, it could alter the steering characteristics of the vehicle – this could pose an accident hazard for vehicle occupants and other road users (PRA 2016/15432).
2015-16 Mercedes-Benz R172 SLK: ESP may apply brakes after automatic braking intervention
In May 2017, a recall was issued for Mercedes-Benz R172 SLK vehicles that were available for sale from 1 May 2015 to 31 December 2016. In these vehicles, the Electronic Stability Program (ESP) software did not conform to specifications. In rare cases, this could cause the brakes to remain slightly engaged after an automatic brake intervention by a driver assistance system (e.g. cruise control), and result in continuous vehicle deceleration. The braking system may also overheat and reduce the vehicle’s braking capability, increasing the risk of injury to vehicle occupants and other road users (PRA 2017/16076).
Problems and faults: Mercedes-Benz R172 SLK-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 R172 SLK 200 and SLK 250: M271 EVO camshaft adjuster/sprocket failure
Background
For the M271 and M271 EVO engines, each camshaft has a camshaft adjuster/sprocket mounted to the front of it. The camshaft adjuster is mounted on a bearing so that it can rotate separately from the camshaft and is driven by timing chain. Furthermore, a solenoid is bolted onto the camshaft adjuster and attached to the end of the camshaft. As the camshaft adjuster is rotated by the timing chain, the sprocket can control the offset of the camshaft.
While camshaft adjuster failures are a recognised problem for the M271 engine, there have also been reports for the M271 EVO engine. For the M271 EVO engine, however, it is understood that Mercedes-Benz changed the design of the camshaft adjuster, the aluminium cover for the camshaft adjuster and solenoid for the 2012 model year. As such, post-2012 M271 EVO engines should not experience this problem.
Camshaft adjuster/sprocket failure
The camshaft adjuster for the M271 engine is made from cast iron and its operation against the single-row steel timing chain causes the teeth to wear prematurely; while the teeth can potentially break off, this is relatively rare. Wear to the camshaft adjuster can cause:
- The engine’s valve timing to be advanced or retarded;
- The timing chain to stretch; and,
- At worst, changes to engine timing can cause the pistons and valves to collide – such engine damage is extremely serious.
Merc271 provides re-manufactured camshaft adjusters in which the original gear face has been removed and a high-tensile, surface hardened steel gear profile has been applied to make it significantly stronger. Some owners, however, recommend replacing the timing chains and camshaft adjusters as a preventative measure every 130,000 kilometres.
Symptoms
Symptoms of camshaft adjuster failure include:
- A rattling noise on start-up caused by play of the timing chain and camshaft adjuster teeth;
- Uneven running and a rough idle;
- Diagnostic trouble codes (DTCs) related to camshaft timing.
Replacement
Replacing the camshaft adjuster requires:
- The solenoid and valve cover to be removed;
- The tension on the timing chain to be released; and,
- The camshaft adjuster to be removed from the camshaft.
Mercedes-Benz R172 SLK 350: engine rattle noise after start-up
In December 2015, Mercedes-Benz issued Service Bulletin LI05.10-P-056435 Version 10 for Mercedes-Benz R172 SLK 350 vehicles that had M276 engines with the following engine numbers:
- M2768: up to engine 2768xx 30 001281; and,
- M2769: up to engine 2769xx 30 406603.
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).
