Mercedes-Benz C 220 D
Pre-chamber four-cylinder, successor to the OM601. Economical and reliable but outdated in terms of power. Check glow plugs regularly.
Dependable Everyday Diesel
70 kW prechamber diesel performs its duties without emotion. The W202 deserves better — but the engine cannot offer it.
Engine Weaknesses 6
The electronically controlled Lucas EPIC distributor injection pump is inherently fault-prone. Internal leaks and defective solenoid valves cause limp mode or complete failure. Replacement with a Bosch pump is recommended.
Symptoms: EDC warning light, power drop to ~3,000 rpm (limp mode), sporadic starting difficulties, engine runs on after switching off
The aluminium cylinder head is more prone to trapping glow plugs than cast iron heads. When changing, the plug can snap off, forcing expensive head removal.
Symptoms: Cold start problems, rough running below 5 degrees C, glow plug warning light flashing irregularly
The OM604 has an aluminium cylinder head that warps when overheated. Head gasket failures documented from approximately 114,000 km, with normal use usually significantly later.
Symptoms: Coolant loss without visible external leak, white smoke from exhaust, oil film in coolant, engine overheats
The hydraulic chain tensioner loses oil pressure at high mileage, causing cold-start rattling. In the worst case the chain jumps.
Symptoms: Rattling at cold start for 1–3 seconds; with advanced wear, continuous rattling and engine speed fluctuations
The thin 6mm intake valve stem on the OM604 elongates beyond the compensation range of the original hydraulic tappets. BGA repair tappets (1 mm shorter) allow a cost-effective repair.
Symptoms: Poor cold-start behaviour, engine barely starts in sub-zero temperatures, rough running after starting that normalises only after warm-up
Engine mounts on the OM604 in the W202 tend to wear from approximately 150,000–200,000 km. Aftermarket mounts (Corteco) at €24–€50 per unit. Complete set with fitting approximately €460.
Symptoms: Vibrations at idle, judder during gear changes, droning at approximately 80 km/h, noticeable vibrations at gear lever
Vehicle Weaknesses 7
Front strut towers corrode and can break away from the bodywork. Safety-critical failure — affected parts are riveted.
W202 strongly prone to through-rusting at sills, wheel arches and door lower edges. Absence of factory sealant up to 1997 accelerates corrosion. Strut top rust is safety-critical.
Front control arms trap water in internal cavities. Blocked drain holes lead to internal rust. In extreme cases the wheel can detach from the control arm — safety-critical.
Rust on door edges, sills, wheel arches and under door seals. A faulty primer-bath process encouraged early rust formation. First build years particularly affected.
Rubber bushes in the front wishbones wear and develop play. Anti-roll bar mountings wear noticeably quickly.
Wiring breaks affect electric seats and steering column stalks. Classic ageing problem from brittle cable insulation.
Window regulator control units fail through water ingress. SAM module controls lighting and wipers — failures typical on older W202.