Faults and recalls.

Engine / equipment

OM651 2.1/2.2 CDI (C 200/220/250 CDI, E 200/220/250, GLK, Vito, Sprinter)

Period mentioned

2008 onwards

Symptoms

Chain rattle on a cold start; on early units, loud injector knocking; coolant loss from the plastic coolant manifold or the EGR cooler.

Possible cause described

Plastic chain guide and a hydraulic tensioner that loses pressure (the chain is at the rear). Early units used problematic piezo injectors that Mercedes replaced in a campaign.

Check for the garage

Listen to a cold start, check the dealer's injector campaign history and check the coolant level.

Cost cited in the source

Chain: approx. €1,500–3,000 (estimate)A rough figure from the original database, not an up-to-date quote.

Sources from the original database

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

M271 1.8 Kompressor / CGI (C 180/200 W203 and W204, E 200 W211/W212, CLK 200, SLK 200)

Period mentioned

2002–2015

Symptoms

Rattle for 2–3 seconds or more on a cold start; engine light for camshaft timing deviation.

Possible cause described

A single-row chain that stretches and cast-iron camshaft adjusters whose teeth wear. On later versions the hydraulic tensioner fails more often.

Check for the garage

Listen to a cold start, read timing fault codes and check the chain replacement history.

Cost cited in the source

€1,500–3,000A rough figure from the original database, not an up-to-date quote.

Sources from the original database

Engine / equipment

M156 6.2 V8 AMG (C 63 W204, E 63 W211 and W212 until 2011, CLK 63, CLS 63, ML 63, S 63 and CL 63 until 2010, SL 63)

Period mentioned

2006–2015

Symptoms

Coolant loss, coolant in the oil or white smoke (broken head bolts); rattle or ticking on start-up (camshaft and lifter wear).

Possible cause described

Cylinder head bolts that break on engines up to 2012 (Mercedes bulletin from 2011) and nodular cast-iron camshafts that wear together with the lifters, mainly on the intake side (bulletin from 2009).

Check for the garage

Overnight cooling system pressure test, oil analysis and camshaft inspection with a borescope.

Cost cited in the source

Major engine repair (several thousand euros)A rough figure from the original database, not an up-to-date quote.

Sources from the original database

Engine / equipment

M272 V6 (280, 300, 350) and M273 V8 (450, 500, 550) in the C, E, CLK, CLS, SLK, ML, GL, R, S and CL

Period mentioned

2004–2008 (engines below serial number 2729..30 468993)

Symptoms

Engine light with P0016 and P0017 (1200 and 1208 on Mercedes diagnostics), rattle on start-up, hesitation, misfires and, in severe cases, stalling.

Possible cause described

Balance shaft sprocket (M272) or timing idler gear (M273) made from metal that is too soft: the teeth wear, the chain goes slack and the timing slips. Mercedes changed the material in mid-2008.

Check for the garage

Compare the engine serial number with the 2729..30 468993 cut-off, read cam correlation codes and, if in doubt, inspect the sprocket with a borescope. First rule out the cam adjuster magnet (a cheap fault).

Cost cited in the source

Engine-out repair: over €3,700 (converted from dollars)A rough figure from the original database, not an up-to-date quote.

Sources from the original database

Engine / equipment

OM646 2.1/2.2 CDI (C 200/220 CDI W203 and W204, E 200/220 CDI W211, Vito, Sprinter) and the 2.2 CRD in the Chrysler PT Cruiser

Period mentioned

2002–2010

Symptoms

Puffing or “chuffing” at idle, a diesel smell under the engine cover and a hard black crust around the injectors; power loss from sooted intake flaps or turbo.

Possible cause described

The copper washer under each injector fails and combustion gases escape, carrying diesel and oil that harden into a black crust (“black death”). Soot also seizes the intake flaps and turbo mechanism. Otherwise it is a very robust engine.

Check for the garage

Remove the engine cover and look for black residue around the injectors, listen at idle and check the intake flaps.

Cost cited in the source

Injector washers: approx. €200–800 depending on how advanced the crust isA rough figure from the original database, not an up-to-date quote.

Mileage cited in the database: from 150,000 km. This is not a maintenance interval and does not predict a failure.

Sources from the original database

Engine / equipment

M270 and M274 1.6/2.0 turbo petrol (A, B, CLA, GLA, C, E, GLC, SLC)

Period mentioned

2012–2020

Symptoms

Chain rattle on cold starts; engine light with camshaft timing codes (for example P0016 or P001685); oil leaks at the camshaft adjusters; slow coolant loss.

Possible cause described

The hydraulic tensioner loses pressure overnight and the plastic guides wear, especially with long oil change intervals. The camshaft adjuster magnets leak oil (common between 65,000 and 110,000 km) and the plastic thermostat housing cracks.

Check for the garage

Listen to a cold start, read camshaft codes, look for oil on the adjuster magnets and coolant residue at the thermostat. Use Mercedes 229.5 oil.

Cost cited in the source

Chain and tensioner: approx. €320–1,650 (converted from dollars)A rough figure from the original database, not an up-to-date quote.

Mileage cited in the database: 65,000–110,000 km. This is not a maintenance interval and does not predict a failure.

Sources from the original database

Engine / equipment

OM607 and OM608 1.5 diesel of Renault origin (K9K): A 160/180 CDI and d, B 160/180, CLA 180 CDI and d, GLA 180 d, Citan

Period mentioned

2012–2026

Symptoms

Smoke, hesitation or hard starting (injectors); unstable idle, power loss and engine light (EGR); particulate filter warning in town use; oil consumption.

Possible cause described

It is Renault's 1.5 dCi with Mercedes electronics. On the OM607 the injectors are the main weak point; the OM608 that replaced it in 2018 has fewer problems. The EGR builds up carbon, mostly between 60,000 and 100,000 km, and the particulate filter clogs on short trips.

Check for the garage

Identify the engine (OM607 until 2018, OM608 after), measure injector balance rates, check the EGR and particulate filter status and watch the oil level.

Cost cited in the source

Depends on the part (injectors, EGR or turbo); the sources consulted give no reliable figuresA rough figure from the original database, not an up-to-date quote.

Mileage cited in the database: 60,000–100,000 km. This is not a maintenance interval and does not predict a failure.

Sources from the original database

Engine / equipment

OM654 2.0 and OM656 3.0 diesel (C, E, S, GLC, GLE, GLS, G-Class from 2016)

Period mentioned

2016–2026

Symptoms

AdBlue or emissions warnings with a start countdown; particulate filter warning; power loss or rough idle from a dirty EGR.

Possible cause described

These are robust engines; faults concentrate in the emissions system. The AdBlue system (injector, NOx sensors and SCR catalyst) sometimes fails, especially in the cold, and the particulate filter and EGR foul if the car mostly does short trips.

Check for the garage

Read AdBlue and NOx sensor codes with Xentry, check the particulate filter regeneration history and how the car is used (short trips).

Cost cited in the source

AdBlue system: approx. €500–1,200; particulate filter: €1,000–2,000A rough figure from the original database, not an up-to-date quote.

Mileage cited in the database: from 100,000 km. This is not a maintenance interval and does not predict a failure.

Sources from the original database

Engine / equipment

9G-Tronic automatic gearbox (725.0 and 725.1): C-Class W205 and W206, E W212 and W213, CLS, S W222 and W223, GLC, GLE, GLS, SL and SLC

Period mentioned

2013–2026

Symptoms

Harsh or jerky shifts (especially 1st to 2nd and when cold), vibration, delayed shifts or limp mode; sometimes the gear will not engage from N to D. Codes P073E00 and P07B700.

Possible cause described

Mercedes acknowledges in a technical bulletin complaints of harsh shifts, shudder and limp mode with various causes. In the early years (2014–2016) it is usually software or adaptation rather than mechanical damage; in other cases the pressure sensor built into the gearbox control unit fails.

Check for the garage

Follow the Mercedes bulletin: reproduce the complaint, save the EEPROM, check the oil level, run the Xentry valve flush, update engine, gearbox and shift unit software and perform the standstill adaptation. If it persists, check the control unit.

Cost cited in the source

Software update and adaptation: the most common and cheapest fix; repairing or replacing the control unit costs considerably more (the sources give no comparable figures)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

Vaneo W414 with radio-controlled locking.

Period mentioned

2002–2005.

Symptoms

Unlocks; interior lamp remains on.

Possible cause described

Tensioned wire detaches from sliding-door contact.

Check for the garage

Check contact and harness; replace switch if disconnected and remove strain.

Cost cited in the source

No verified estimate.A rough figure from the original database, not an up-to-date quote.

Sources from the original database

Engine / equipment

Air conditioning in documented 170, 208 and W210 platforms.

Period mentioned

No year cutoff published; verify platform and A/C.

Symptoms

Compressor fails to engage or operates intermittently.

Possible cause described

Pressure sensor/switch may give incorrect values.

Check for the garage

Compare scan-tool and high-side gauge pressure; replace sensor if difference >2 bar.

Cost cited in the source

No verified estimate.A rough figure from the original database, not an up-to-date quote.

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