Mercedes-Benz E 250
Modern turbocharged four-cylinder with direct injection and piezo injectors. Successor to the M271. Less susceptible to timing chain issues. Good balance of power and economy.
Solid Basis
155 kW — everyday-capable power, without excitement.
Engine Weaknesses 6
The high-pressure fuel pump on the M274 is driven by a lobe on the intake camshaft. Wear on the drive lobe or pump follower leads to pressure drop.
Symptoms: Metallic ticking from engine area, starting problems or extended cranking, power loss, fault code P0087
On the M274 too, the camshaft adjuster solenoids develop leaks. Oil penetrates the wiring harness by capillary action and can damage the engine ECU.
Symptoms: Fault code P0010, CEL, oil traces at camshaft connectors, lambda sensor failure, in severe cases ECU failure
Primary weak point of the M274: the electric thermostat sits deep in the engine block and is hard to reach. Replacement takes around 3 hours.
Symptoms: Engine does not reach operating temperature or overheats, temperature fluctuations, fault codes P0597–P0599
The PCV valve on the M274 clogs or breaks. Fault code P052E. Parts are inexpensive (~€63), but installed hidden under the engine ECU.
Symptoms: Fault code P052E, CEL, power loss, fault returns immediately after clearing
The M274 petrol engine has two NOx sensors that frequently fail. Each sensor costs around €600 as a part; with both sensors the repair bill quickly reaches €1,500.
Symptoms: Check engine light, NOx sensor fault code, elevated exhaust values, possible limp mode
The M274 with direct injection and no port injection tends to carbon deposits on intake valves like all GDI engines. Walnut blasting every 60,000–80,000 km is recommended.
Symptoms: Stumble under partial load, rough idle, slight power loss
Vehicle Weaknesses 14
Rear subframe rusts from the inside out. Faulty factory sealant allows water ingress. Flagged as safety-critical at MOT.
W212 steel rear subframe with powder coating cracks over time and allows moisture in. Rusts from the inside. Mercedes replaces as a goodwill gesture. Safety-critical.
Brake lines above the rear axle corrode through after 8–10 years. Brake fluid loss leads to brake failure. MOT refusal.
Airmatic system fails through compressor defects and air bag leaks. Vehicle drops. Rear axle often has to be removed.
Rear axle corrodes through with age; suspension mounting points are flagged at MOT. Goodwill repairs possible but time-limited.
Brake lines corrode at two to twelve times the rate of comparable vehicles according to MOT data.
The rear axle is prone to severe rust-through from the inside at the weld seams of the subframe. The problem goes unnoticed for a long time. Mercedes granted goodwill replacements in some cases.
Worn joints and strut rod ends on the front axle are a recurring problem. Classic wear pattern at higher mileages.
Drain holes in the sills clog up; water collects and promotes rust from the inside.
Worn ball joints and strut top mounts on the front axle are a recurring problem. Individual owners reported multiple repairs.
The soft top tends to develop cracks in the fabric after about 10 years. Ignored cracks lead to water ingress, mould growth and control unit damage.
The drain channels in the sills clog regularly, causing water accumulation and corrosion in the sill area. Control units in the floor area can become damp.
Knocking and rattling from the front axle on uneven road surfaces. Causes: worn ball joints, anti-roll bar bushings.
The parking brake is regularly flagged at MOT. Corrosion from infrequent use causes it to seize or fail.