Mercedes-Benz Clase E (W211) E 280 / 320 CDI (OM642, desde 2005) common problems.

Engine / equipment

OM642 3.0 V6 CDI/BlueTEC (280/300/320/350 CDI, ML, GL, R, Sprinter)

Period mentioned

2005 onwards

Symptoms

Oil pooling in the engine's V, burning oil smell, drips under the engine; or a hiss or chirp next to an injector with an exhaust smell.

Possible cause described

The oil cooler seals (in the engine's V) degrade. Separately, injector washers leak combustion gas and carbon builds up around the injector.

Check for the garage

Visual inspection of the engine's V and the base of the injectors.

Cost cited in the source

Oil cooler seals: labour-heavy, approx. €800–1,800 (estimate)A rough figure from the original database, not an up-to-date quote.

Sources from the original database

Engine / equipment

7G-Tronic automatic gearbox (722.9) in the C, E, S-Class, ML, GL, SLK, Sprinter…

Period mentioned

2004 onwards (more failures in 2004–2008)

Symptoms

Gearbox stuck in 2nd or 3rd (limp mode), harsh shifts, delay engaging D or R, gearbox warning often without an engine light; turning off and restarting clears it for a while.

Possible cause described

The conductor plate (the control unit with built-in speed sensors) fails from heat and vibration. Oil leaks through the 13-pin connector are also common.

Check for the garage

Diagnose with Xentry/STAR to see the sub-codes (a basic reader only shows P0700). Check for oil in the gearbox connector.

Cost cited in the source

Approx. €1,400–2,800 (estimate)A rough figure from the original database, not an up-to-date quote.

Sources from the original database

Engine / equipment

AIRMATIC air suspension: E-Class W211, W212 and W213, S W220 to W223, CLS, CL, ML W164, GL, GLE and GLS

Period mentioned

2002–2026

Symptoms

One corner sags overnight, suspension fault warning, the compressor runs a lot or a compressor overheated message appears; eventually the car sits low and rides hard.

Possible cause described

The air bellows on the struts leak with age, often at the upper crimp rings, and the compressor overworks until it burns out. The valve block and lines also leak, and the compressor relay (in the rear SAM on W221, W222 and W213) and ride height sensors fail.

Check for the garage

Spray soapy water on bellows, lines and valve block; read each corner's data with Xentry; check the compressor fuse and relay. Do not replace the compressor without fixing the leak first, or the new one will fail soon.

Cost cited in the source

Compressor: approx. €600–1,200 at an independent garage (converted from Canadian dollars); bellows: depends on the cornerA rough figure from the original database, not an up-to-date quote.

Mileage cited in the database: 95,000–115,000 km. This is not a maintenance interval and does not predict a failure.

Sources from the original database

Engine / equipment

Sensotronic Brake Control braking system: E-Class W211 and CLS C219 up to model year 2006, and SL R230

Period mentioned

2002–2012

Symptoms

Red messages in the cluster such as “STOP VEHICLE”, “Brake defective” or “Reduced braking power – visit workshop”, a hard pedal or little assistance, and pump noises when braking or opening the door. In a complete failure only the front wheels brake, using foot force alone.

Possible cause described

SBC brakes by wire: a control unit calculates the pressure for each wheel and a pump with a high-pressure accumulator produces it. The hydraulic unit has a limit on operating cycles; when it is reached, it warns and reduces assistance. The pump, accumulator and wiring also fail, and old brake fluid or incorrect bleeding make it worse. Mercedes issued several recalls and, in the US, extended the warranty on several system components to 25 years.

Check for the garage

With any red brake warning, stop driving and call for assistance. At a Mercedes dealer: read the SBC control unit with official diagnostics, check open recalls and warranty extensions by VIN, and change the brake fluid only with the procedure SBC requires. The cycles-exhausted warning means replacing the unit, not clearing the code.

Cost cited in the source

No verifiable estimate for Europe. In the US, Mercedes covers the hydraulic unit and other components for 25 years with no mileage limit; ask a dealer whether your VIN has a recall or extension.A rough figure from the original database, not an up-to-date quote.

Sources from the original database

Engine / equipment

722.6 five-speed automatic (5G-Tronic), not the 7G-Tronic: C-Class W203, E-Class W210 and W211, CLK, S-Class W220, ML W163, SLK, SL R230, Vito and Sprinter with this gearbox

Period mentioned

1996–2013

Symptoms

Oil around the electrical connector on the side of the gearbox, harsh shifts or slipping, delayed engagement and limp mode: the car stays in one gear (usually 2nd and reverse after a restart) and the engine light comes on.

Possible cause described

The plastic adapter of the 13-pin connector has O-rings that harden and let oil out. Oil can wick up inside the wiring to the gearbox control unit and damage it. If the problem persists after replacing the connector, there may be oil in the harness, a damaged wire or a conductor plate fault.

Check for the garage

Read the gearbox control unit codes before switching off if possible (a restart can clear them). Look for oil at the connector and, with it unplugged, on its pins and at the control unit plug. According to the service bulletin, the connector should only be removed with gearbox oil below 50 °C to avoid damaging the conductor plate, and the harness must be routed without tension.

Cost cited in the source

Connector adapter: about $15–20 in parts (US prices quoted in the sources), plus the lost fluid; labour extra. If oil has reached the control unit, the repair is bigger.A rough figure from the original database, not an up-to-date quote.

Sources from the original database