Peugeot 406 8 — Problems & Common Faults

A four-cylinder common-rail diesel with variable-geometry turbocharging, and in higher-output versions with two sequential turbochargers (biturbo). Camshaft drive is a hybrid design: a toothed belt drives the first camshaft, the second is linked via a short chain — a snapped belt is an interference-engine risk. Typical weak points include clogged particulate filters from short-distance driving, sticking swirl flaps in the intake tract, and seized injectors in the cylinder head that can damage the head if removed without the right tooling. The turbocharger and common-rail system also wear faster when oil changes are neglected. With clean oil, a working EGR system and timely belt service, very high mileages are achievable.

• !! Turbocharger bearing damage from oil starvation from 150,000 km

  The turbocharger bearings of the DW12 wear when oil quality is poor or change intervals are extended. Carbon deposits in the oil line block lubricant supply and cause turbo damage.

  Symptoms: Whistling from the turbo, blue smoke under acceleration, noticeable power loss, rising oil consumption
  800–2,000 $
  Ad turbocharger DW12 2.2 HDiturbo 407 2.2 HDiGarrett GT1549S
• !! Injectors seized in the cylinder head from 130,000 km

  Moisture accumulation in the injector bores causes the injectors to corrode into the cylinder head. Removal requires special tools and can result in consequential damage to the cylinder head.

  Symptoms: Rough engine running, increased fuel consumption, engine knocking, black smoke
  600–2,500 $
  Ad fuel injector DW12 2.2 HDifuel injector 407 2.2Bosch 0445110036
• !! EGR valve sticks from 100,000 km

  The EGR valve on the DW12 tends to stick from soot deposits, particularly during predominantly short-trip use. The mechanism gets stuck in the open or closed position and disrupts mixture preparation.

  Symptoms: Rough engine running, power loss, engine management light, hesitation under acceleration
  300–800 $
  Ad EGR valve DW12EGR valve 2.2 HDiPeugeot 407 EGR

+ 3 more engine weaknesses + vehicle weaknesses

Proven 1.6L 16V naturally aspirated engine with decent power for the compact class and small MPVs. Timing belt every 120,000 km — if it snaps, the engine is destroyed (interference design). Throttle body and idle air control valve get dirty regularly. Ignition coil pack can fail at high mileage. The sporty TU5JP4 revs higher and is correspondingly more stressed. With consistent maintenance a long-lived, uncomplicated naturally aspirated engine.

• !! Timing belt snap causing engine destruction from 120,000 km

  The TU5 is an interference engine — if the timing belt snaps, pistons hit valves. Change interval is 120,000 km or 10 years, but is frequently missed. Always ask for proof of belt change when buying used.

  Symptoms: Engine suddenly dies and will not restart, metallic crashing noise when attempting to start
  300–600 $
  Ad timing belt TU5JP4timing belt kit Peugeot 206 1.6 16Vtensioner pulley TU5
• ! Valve stem seals worn from 130,000 km

  From around 130,000 km the valve stem seals tend to harden. Oil enters the combustion chamber, especially visible as blue smoke on cold start. Oil consumption rises to 0.5–1 L/1,000 km.

  Symptoms: Bluish smoke on cold start, increased oil consumption, oil film on spark plugs
  400–800 $
  Ad valve stem seal TU5JP4valve stem seal Peugeot 206 1.6 16V
• ! Thermostat and cooling system leaks from 100,000 km

  The plastic thermostat housing becomes brittle over time. Coolant hoses near the water pump are prone to cracking. Engine fails to reach operating temperature or overheats when the thermostat fails.

  Symptoms: Engine does not reach operating temperature (stays around 75°C), coolant loss, heater stays cold
  100–300 $
  Ad thermostat Peugeot 206 1.6 16Vcoolantschlauch TU5JP4water pump TU5

+ 3 more engine weaknesses + vehicle weaknesses

Large 2.0-liter naturally aspirated engine with 16V technology from the EW family. A timing belt engine, fundamentally robust and powerful. The sporty EW10J4 variant runs under significantly higher stress. Timing belt replacement with water pump every 120,000 km at the latest — if it snaps, the engine is destroyed. The throttle body gets dirty regularly. A reliable, torque-rich naturally aspirated engine with proper maintenance that easily reaches high mileages.

• !! Ignition coil failure from 80,000 km

  The ignition coils of the EW10 fail regularly and cause misfires. On the 206 there was even a TSB with a wiring modification (capacitor on the connector). Individual cylinders drop out.

  Symptoms: Juddering under acceleration, engine management light, increased fuel consumption, rough idle
  80–300 $
  Ad ignition coil EW10J4ignition coilnset Peugeot 307 2.0
• !! Camshaft sensor failure from 90,000 km

  The camshaft position sensor of the EW10 is prone to dirty contacts and intermittent failures. The engine can stall under throttle and requires careful application of the accelerator.

  Symptoms: Engine stalls when blipping the throttle, warm-start problems, sporadic fault codes
  50–200 $
  Ad camshaftnsensor EW10camshaftnpositionsgeber Peugeot 2.0 16V
• !! Electric thermostat defective from 80,000 km

  The electric thermostat of the EW10A fails frequently and causes overheating issues or too-low operating temperature. Converting to a mechanical thermostat is a well-known workaround.

  Symptoms: Temperature gauge fluctuates significantly, engine does not reach operating temperature, overheating warning
  100–350 $
  Ad thermostat EW10 elektrischthermostat Peugeot 307 2.0 16V

+ 3 more engine weaknesses + vehicle weaknesses