Recalls & faults: Mercedes-Benz W251 R-Class (2006-13)

Recalls: Mercedes-Benz W251 R-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 W251 R-Class

Mercedes-Benz W251 R-Class: accelerator pedal nuts

In September 2007, a recall was issued for Mercedes-Benz W251 R-Class vehicles due to one or both of the nuts securing the accelerator pedal missing or not having been fitted correctly (PRA 2007/9495).

2006-07 Mercedes-Benz W251 R-Class Diesel: loss of power and failure to start

In June 2008, a recall was issued for Mercedes-Benz W251 R-Class vehicles fitted with the 3.0-litre OM642 V6 turbo-diesel engine that were manufactured between May 2006 and October 2007. In these vehicles, an open circuit in the chip housing of the crankshaft position sensor could occur due to contamination of the silicone during its manufacture. When the problem occurred, the engine would lose all power and not restart. To fix, the crankshaft position sensor was replaced (PRA 2008/10085).

2009-11 Mercedes-Benz W251 R-Class Diesel: fuel leak

In January 2012, a recall was issued for Mercedes-BenzW251.II R 300 CDI, W251.II R 350 CDI and W251.III R 300 CDI models fitted with the OM642 3.0-litre turbo-diesel engine and manufactured from November 2009 to July 2011. In these vehicles, the fuel filter may leak diesel fuel and pose a potential hazard to other road users (PRA 2012/13002).

2009-13 ‘model year’ Mercedes-Benz W251 R-Class: Takata airbag recall

In May 2018, recall RC2469 S2 was initiated for 2009-13 ‘model year’ Mercedes-Benz W251 R-Class vehicles. In these vehicles, the driver’s airbag contained propellant that could absorb moisture over time. In the event of a collision which triggered the airbag, the airbag could deploy too aggressively and the metal inflator housing could explode/rupture due to excessive internal pressure. If this occurred, metal fragments could be propelled through the airbag cushion and towards vehicle occupants – these fragments posed a risk of serious injury or fatality. For the VINs of the recalled vehicles, please see PRA 2018/16814.

Problems and faults: Mercedes-Benz W251 R-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.

2005-06 Mercedes-Benz W251 R 350: M272 balancer shaft sprocket gear failure

In May 2011, Mercedes-Benz issued service bulletin LI03.30-P-050027 for Mercedes-Benz W251 R 350 vehicles with M272 V6 engines which:

• Had serial numbers prior to 2729..30 468993; and,
• Were manufactured prior to October 2006.

In these vehicles, premature wear of a gear on the balancer shaft sprocket could cause the positioning of the camshafts in the right cylinder bank to be impaired (relative to the crankshaft). According to the service bulletin, this wear of the balancer shaft sprocket could cause the following symptoms:

• Illumination of the check engine light; and,
• Diagnostic trouble codes (DTCs) 1200 or 1208 stored in the ME-SFI control unit.

Owners have experienced failure of the balancer shaft sprocket gear after 95,000 kilometres, accompanied by rough running and illumination of the check engine light. From October 2006 production, a hardened material was used for the sprocket and the timing chain guide wheel (idler) was modified.

For the M272 V6 engine, the repair procedure is as follows:

1. Remove the right front camshaft adjuster cover;
2. Check the balance shaft sprocket for wear using a flexible borescope. In rare cases, a stretched timing chain may be the reason for the DTCs if the sprocket does not exhibit any signs of wear;
3. If worn, replace the balance shaft. Note: since the balancer shaft is located inside the engine block, repairs are expensive;
4. Replace the chain tensioner (part number A272 050 01 11);
5. Change engine oil and filter;
6. Drive with engine at high load and rpm for at least 20 km;
7. Change engine oil and filter once more; and,
8. Replace the camshaft adjustment solenoids.

Mercedes-Benz W251 R 350 and R 500: M272 and M273 cam plug oil leak

Mercedes-Benz M272 V6 and M273 V8 engines that were produced prior to June 2008 may experience oil leaks (or ‘seepage’) from the round plastic expansion plugs (‘cam plugs’) on the back of the cylinder heads. There were two different size cam plugs:

• Part number A000 998 55 90: two small expansion plugs (approximately 2.5 cm diameter); and,
• Part number A000 998 56 90: one large small expansion plug (for engines without vacuum pump).

To fix, the existing plugs were to be removed, the opening cleaned and new plugs fitted; no sealer was to be used in the installation of the new plugs. New cam plugs that were not susceptible to oil leaks were phased into production in June 2008.

Mercedes-Benz W251 R 350 and R 500: actuator cam for VIM

For Mercedes-Benz W251 R 350 (2006-12) and R 500 (2006-11) vehicles, the plastic actuator cam in the variable intake manifold (VIM) for the M272 V6 and M273 V8 engines is susceptible to failure. Symptoms of a broken actuator cam include:

• Rough idle;
• A loss of power (particularly at low and mid-range engine speeds);
• Illumination of the check engine lights; and,
• Diagnostic Trouble Codes (DTCs) such as P2004, P2005, P2006, P2187 and P2189.

Due to the venting of oil from the PCV (positive crankcase ventilation) system, carbon deposits can accumulate on the swirl flaps inside the variable intake manifold. These carbon deposits increase the resistance on the plastic actuator cam and this can cause it to break. Other parts can also fail as a result, including the swirl flaps, the actuator mounting arms and the vacuum diaphragms.

AustralianCar.Reviews understands that the original equipment supplier for the intake manifold is Pierberg and that Mercedes-Benz’s repair involves replacing the entire intake manifold since they do not supply replacement actuator cams. However, eEuroparts.com sell intake manifold repair kits that replace the plastic actuator cam with a metal component and can be used for DIY repairs. However, the intake manifold also needs to be cleaned as part of any repair. For further information about this problem, please see:

• eEuroparts.com: Fixing Mercedes-Benz Intake Manifold Woes; and,
• eEuroparts.com: Mercedes-Benz Intake Manifold Repair DIY.

Mercedes W251 R 280 CDI, 300 CDI, 320 CDI and 350 CDI: knocking or ticking noise at idle

In February 2013, Mercedes-Benz issued Service Bulletin LI03.20-P-048278 for Mercedes-Benz W251 R-Class models that had 3.0-litre OM642 diesel engines – this included the R 280 CDI, R 300 CDI, R 320 CDI, R 350 CDI and R 350 BlueTEC.

According to LI03.20-P-048278, these vehicles may exhibit an intermittent knocking or ticking noise at idle and at engine speeds up to 1500 rpm. Specifically,

• The noise would occur after a mileage of approximately 32,000 kilometres or after an oil change;
• The noise could be clearly heard in the area of the first crankshaft main bearing;
• The noise would not be present when the poly-V belt was removed;
• The noise was a pulse-like crackling that occurred at irregular intervals; and,
• 20 pulses (ticking) represented a ‘justifiable complaint’.

These symptoms were attributed to a ‘run-in effect’ or defect of the first crankshaft main bearing shells. To verify the complaint, the poly-V belt was to be removed to see if that eliminated the noise. To fix, the bearing shells of the first crankshaft main bearing were to be replaced.

Mercedes-Benz W251 R 320 CDI: OM642 engine

• Pre-2010 OM642 engines were susceptible to oil cooler leaks due to heat-related seal degradation. In 2010, Mercedes-Benz introduced more durable Viton seals which could be identified by their purple colour (the previously used seals were orange).
• The TWC temperature sensor (part no. A005 153 40 28) was susceptible to failure and was subsequently replaced with part no. A007 153 74 28. When the temperature sensor fails, the check engine light may illuminate and issue the OBD-2 diagnostic code P2031.
• The positive crankcase ventilation system vents to the inlet of the turbocharger. However, the vented air may contain too much oil to easily pass through the swirl motor valves which are downstream of the turbocharger. Once this oil and sludge begins to accumulate, the swirl motor valves may become inoperative and blow a fuse that controls other sensors which are required for the engine and emissions systems to operate properly. As a result, the vehicle will enter ‘limp home’ mode and limit engine speed to 3000rpm.

Problems and faults: Mercedes-Benz W251 R-Class

• Snapping or groaning noises from the steering column when turning may be due to the upper steering shaft bearing failing.
• The steering wheel buttons may stop working due to an internal short-circuit. To fix, the steering wheel may need to be replaced.
• Where fitted, the air suspension may stop working and an ‘Airmatic – Visit Workshop’ message may appear due to the wiring harness insulation rubbing off and the wire short-circuiting.
• The door mirrors may not fully retract or open due to a loose electrical connection or a lack of lubrication on their pivots.
• The power-operated tailgate may reverse directions when closing due to a loose bolt for the gas strut.
• The tailgate may not open, requiring the body control module to be reprogrammed.
• A ‘tailgate open’ message may appear when the tailgate is closed – if so, a revised locking mechanism needs to be fitted. If the tailgate intermittently malfunctions, the latch may need to be replaced.
• The valve on the spare tyre may have been damaged during its original mounting and the tyre may not retain air unless the valve (or wheel and tire assembly) is replaced.