Recalls & faults: Mercedes-Benz A209 CLK Cabriolet (2003-09)

Recalls: Mercedes-Benz A209 CLK Cabriolet

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 A209 CLK Cabriolet

• In March 2004, a recall was issued for Mercedes-Benz A209 CLK Cabriolet vehicles manufactured between August 2003 and October 2003 due to the possibility that the tongue of the seat belt may not belt may not fully engage in the seatbelt buckle (PRA 2004/6890).
• In September 2004, a recall was issued for Mercedes-Benz A209 CLK Cabriolet vehicles for potential component failure due to wiring in the side airbags, requiring rectification of the pin allocation (PRA 2004/7221).

Problems and faults: Mercedes-Benz A209 CLK Cabriolet

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 A209 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 A209 CLK 240 and CLK 320 (M112 V6): oil leak from camshaft adjuster solenoid seal

In the USA, a service bulletin was issued in April 2011 for Mercedes-Benz vehicles with M112 V6 engines (such as the CLK 240 and CLK 320).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 A209 CLK 200 Kompressor: M271 engine and carbon build up

For Mercedes-Benz A209 CLK 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 A209 CLK 280 and CLK 350: M272 balancer shaft sprocket gear failure

In May 2011, Mercedes-Benz issued service bulletin LI03.30-P-050027 for Mercedes-Benz A209 CLK 280 and CLK 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.

2006 Mercedes A209 CLK 500: M273 worn timing chain guide gear

In May 2011, Mercedes-Benz issued service bulletin LI03.30-P-050027 for Mercedes-Benz A209 CLK 500 vehicles with M273 V8 engines which:

• Had serial numbers prior to 2739..30 088611; and,
• Were manufactured prior to September 2006.

In these vehicles, a worn guide gear for the timing chain 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.

From September 2006 production, a harder material was used for the timing chain guide wheel.

For the M273 V8 engine, the repair procedure is as follows:

1. Remove the right front camshaft adjuster cover;
2. Check the timing chain guide wheel for wear using a flexible borescope;
3. If worn, replace the guide gear (part number A273 050 06 05) of the chain drive;
4. Replace the chain tensioner;
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 A209 CLK 280, CLK 320 and CLK 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 A209 CLK 280, CLK 350 and CLK 500: actuator cam for VIM

For Mercedes-Benz A209 CLK 280 (2005-09), CLK 350 (2005-09) and CLK 500 (2006-10) 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-Benz A209 CLK 240 and CLK 320: M112 V6 crankshaft position sensor

For Mercedes-Benz A209 CLK 240 and CLK 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.

Problems and faults: Mercedes-Benz A209 CLK Cabriolet

• The convertible roof may jam when lowering due to a faulty hydraulic cylinder that requires replacement with a redesigned unit.
• The boot may not open due to a faulty switch for the convertible roof mechanism.
• Rumbling or squealing noises from the air conditioning compressor may be due to a faulty pulley or bearings; improved components were subsequently released.
• The alternator may not adequate recharge the battery due to a defective internal voltage regulator.
• The air conditioning (blower) motor may stop working or only work intermittently due to an internal circuit breaker in the air conditioning (blower) motor regulator that requires replacement.
• A whistling or squealing noise from the brakes as they are released may be due to a fault with the brake booster.
• The cruise control function may not operate if all four tyres are not the same size or due to a lack of rotation.
• The horn may independently sound due to inadequate clearance between the horn contacts and the airbag assembly in the steering wheel.
• The power adjustable front seats may stop working due to the seat control module failing.
• The rear head restraints may not lock due to a faulty actuator.
• The tail-light bulbs may burn-out prematurely; this may be fixed by installing a jumper harness with greater resistance that reduces the voltage by one volt.
• Transmission fluid may leak from the electrical connector and travel through the wires to the transmission control unit; if so, the connector and O-rings will need to be replaced.