Recalls & faults: Mercedes-Benz W203 C-Class sedan (2000-07)

Recalls: Mercedes-Benz W203 C-Class sedan

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 W203 C-Class sedan

Mercedes-Benz W203 C-Class Sedan with sunroof: glass panel may separate

In August 2020, recall campaign RC2752 was issued for Mercedes-Benz W203 C-Class Sedans that had sunroofs. In these vehicles, the durability of the bonding between the sunroof glass panel and the sliding roof frame may not meet specifications and the glass panel may separate from the vehicle. If this occurred, there was an increased risk of a collision and risk of injury to road users. For the VINs of the recalled vehicles, please see PRA 2020/18467.

Problems and faults: Mercedes-Benz W203 C-Class Sedan

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 W203 C 180 Kompressor and C 200 Kompressor: camshaft adjuster/sprocket failure

Background
For the M271 engine, 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.

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 W203 C 240 and C 320 (M112 V6): oil leak from camshaft adjuster solenoid seal

In the USA, Mercedes-Benz issued a service bulletin in April 2011 for the following vehicles:

• 2004 Mercedes-Benz C 240 (M112 V6); and,
• 2002-04 Mercedes-Benz C 320 (M112 V6).

According to the bulletin, the ‘settling properties’ of the camshaft adjuster solenoid seal could cause oil to enter the engine wiring harness(es) through the electrical connection of the camshaft adjustment solenoid via capillary action. For these vehicles, the camshaft adjustment solenoids were to be replaced and an additional adapter connector harness was to be installed at the next service.

2002-04 Mercedes C 180 Kompressor and C 200 Kompressor: M271 engine and carbon build up

For Mercedes-Benz W203 C 180 Kompressor and C 200 Kompressor vehicles powered by the M271 engine, carbon could accumulate:

• On the exhaust valves (causing them to stick); and,
• On the valve guides/springs.

Symptoms of carbon build up include misfiring, increased fuel consumption, illumination of the ‘check engine’ light and the vehicle entering ‘limp home’ mode. If not attended to, the cylinder head may have to be removed to replace the valves and guides. The spark plugs may indicate if the engine has carbon build up –

• If the spark plugs are burnt, this is indicative of a rich fuel mixture that causes carbon to accumulate faster than normal; and,
• If the spark plugs have white spots, the engine may be leaking coolant. If there are white spots, a compression check is recommended.

It is understood that post-2005 M271 engines had re-designed exhaust valves that had greater clearance.

2005-06 Mercedes W203 C 230 and C 350: M272 balancer shaft sprocket gear failure

In May 2011, Mercedes-Benz issued service bulletin LI03.30-P-050027 for Mercedes-Benz W203 C 230 and C 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 different material was used for the balance shaft sprocket.

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.

2005-08 Mercedes-Benz W203 C 230 and C 350: M272 cam plug oil leak

Mercedes-Benz M272 V6 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 W203 C 240 and C 320: M112 V6 crankshaft position sensor

For Mercedes-Benz W203 C 240 and C 320 models with M112 V6 engines, the engine may run rough or hesitate due to water entering the crankshaft position sensor; if so, the sensor and wiring assembly require replacement.

2005-07 Mercedes-Benz W203 C 230 and C 350: actuator cam for VIM

For 2005-07 Mercedes-Benz W203 C 230 and C 350 vehicles, the actuator cam for the variable intake manifold (VIM) in the M272 V6 engine 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-Benz W203 C 220 CDI: OM611 engine and leaking injectors

For the Mercedes-Benz W203 C 220 CDI’s OM611 diesel engine, the injector seal is a copper washer that is susceptible to failure. Failure of the injector seal causes fuel to leak from the cylinder head and symptoms of a leaking injector include:

• A fuel smell (like paraffin oil) inside the passenger compartment;
• A ‘chuffing’ sound from the top of the affected cylinder as combustion gas escapes on the compression stroke;
• A black, shiny ‘coal like’ deposit around the leaking injector or injectors (sometimes referred to as ‘black death’);
• A loss of power; and,
• Increased fuel consumption.

To fix, the engine covers have to be removed to determine which injector(s) are leaking. If carbon deposits are present, they have to be completely cleared and chipped away with a blunt screwdriver/scraper and vacuumed. Furthermore, if an unclamped injector cannot be moved freely by hand, it may have seized. If seized, the injector needs to be removed by a specialist as damage to the injector or head can result in significantly higher repair costs. The injector seat will likely be blackened and carbonised – this needs to be cleaned off; in severe cases, it may need to be re-cut to provide a usable sealing surface.

For further information, please see Mercedes Diesel Injector Advice.

Problems and faults: Mercedes-Benz W203 C-Class sedan

• Knocking noises from the front suspension – particularly on rough roads – may be due to worn torsion bar links as a result of water entering the ball joints through split seals.
• A whistling sound from under the bonnet when the brakes are released may be due to a faulty power brake booster.
• Tapping noises from the fuel tank may require a restrictor to be installed in the fuel vent line.
• The power steering hose may leak at the connection with the rack-and-pinion assembly due to O-ring damage.
• A scraping noise from the transmission tunnel area may be due to insulation drooping and coming into contact with the drive shaft.
• The air conditioning may stop working due to water leaking into the evaporator sensor.
• The battery in the key fob may drain – and its programming erased – if the key is left in the ignition for extended periods (up to 36 hours).
• For early models, the upper radiator support brackets bolts were susceptible to breaking.