Mercedes-Benz CLK 200
Proven four-cylinder with optional supercharger. Robust and long-lived; the supercharged variant has good torque. Supercharger magnetic clutch can wear.
CLK Entry Level With Style
100 kW M111 in the CLK coupé — the styling outpaces the engine power. Even so: light, nimble, beautiful proportions are rewarding.
Engine Weaknesses 6
One of the most common weak points of the M111: the head gasket becomes porous and starts leaking between 75,000 and 150,000 km. Typical for older M111 engines.
Symptoms: Coolant loss without visible leak, white exhaust plume, oil-coolant emulsion, engine overheats
The supercharger magnetic clutch and the K40 relay are weak points on the M111 Kompressor. The clutch no longer engages, supercharger boost is absent. K40 relay is often repairable at low cost.
Symptoms: Sudden power loss from approx. 3,000 rpm, supercharger cuts in sporadically or not at all
If spark plugs are left too long in the M111, the voltage load on the ignition coils increases substantially. Always replace ignition coil and spark plug together.
Symptoms: Stumbling under load, engine misfires, ignition failure in individual cylinders, CEL, rough idle
The mass airflow sensor wears and delivers faulty readings. The direct result is power loss and increased fuel consumption. Cheap replacement part, but often overlooked as the cause.
Symptoms: Hesitation under load, elevated fuel consumption, check engine light, power drop
On the M111 supercharged engine the oil level must deliberately be kept below MAX. A blocked crankcase ventilation pushes oil mist into the intake tract and destroys the mass airflow sensor.
Symptoms: Increased oil consumption, MAF sensor fails frequently, slight blue smoke from exhaust, oily intake duct
The engine mounts on the M111 supercharged engine are stressed more heavily than on naturally aspirated variants due to the additional torque. Replacement approximately €500 at a Mercedes dealer.
Symptoms: Vibrations in the cabin especially under supercharger load, clunking on throttle transitions, increased noise at low revs
Vehicle Weaknesses 5
Design flaw: vibrating trim strips grind away the paint and allow rust to form. Front and rear wheel arches, lower door edges, boot lock area and bumper transitions particularly affected.
Soft-top hydraulic cylinders develop leaks, preventing the roof from opening or closing fully. Hydraulic fluid contaminates the boot. Repair is very costly.
Control arm bushings, tie rod ends and camber struts wear out as mileage increases. Steering becomes imprecise and susceptible to road ruts. Replacements regularly flagged at MOT.
Airbag control units fail and trigger warning lights. Xenon headlight control units fail at a cost of over 1,000 euros per headlight. Wiring harness hardens with age.
The electronic ignition lock increasingly fails to recognise the key reliably with age, the steering lock does not release or the engine does not start. Vehicles from around 150,000 km particularly affected.