Peugeot 508
Powerful PSA diesel for mid-size and SUV applications. Common rail with turbo. Later versions as BlueHDi with SCR cat and AdBlue.
GT saloon
180 hp in the 508 II: strong diesel in a beautiful saloon. Sporty thrust meets French elegance.
Engine Weaknesses 7
The plastic impeller of the water pump can disintegrate from as early as 50,000 km. Fragments enter the timing belt drive and cause the belt to snap with subsequent total engine destruction.
Symptoms: Coolant temperature rises unusually, coolant loss without visible leak, faint grinding or squealing from the timing belt drive, sudden engine shutdown when belt snaps
The dual-mass flywheel wears prematurely, especially on the 107 hp variant. Oil dilution from DPF regeneration accelerates wear. The clutch should always be renewed at the same time.
Symptoms: Squealing or clattering when starting and stopping the engine, pronounced vibrations at idle, juddering when pulling away, knocking at low revs under load
Leaking injectors allow diesel into the engine oil, drastically reducing its lubricity. The rising oil level is often overlooked. This can cause piston and bearing damage.
Symptoms: Diesel smell at the dipstick, oil level rises above maximum, strong exhaust smell inside the car, engine judders or knocks more than usual, increased fuel consumption
After switching off a hot engine the oil lines to the turbocharger can coke up. On the next start the turbocharger briefly runs without lubrication. Mainly affects the more powerful DW10 variants.
Symptoms: Increasing whistling or whining from the turbocharger, oil spots under the car in the turbo area, gradual power loss, blue smoke after the engine has been standing
Internal EGR cooler failure routes coolant into the exhaust gases. Coolant disappears without visible external leak. Repair requires 13.2 hours of labour. Cost 800–2,000 €.
Symptoms: Coolant drops without visible leak, white smoke from exhaust, heater won't warm up
The PSA-proprietary additive (Eolys) is mixed into the fuel and enables regeneration at a lower temperature. A defective additive pump or empty reservoir prevents regeneration and clogs the FAP prematurely. Change interval 120,000–180,000 km.
Symptoms: Warning 'particulate filter will soon clog', increased fuel consumption, power loss, regeneration attempts visible as idle speed fluctuations
The EGR valve seizes with soot deposits or no longer closes fully. The result is warning messages, poor cold-start behaviour and increased particulate output into the filter, causing it to clog faster.
Symptoms: Warning 'exhaust aftertreatment system fault', poor cold-start behaviour, light smoke when accelerating, occasional judder under load
Vehicle Weaknesses 9
The 508 PHEV (plug-in hybrid) was subject to recalls due to potential fire risk from faulty high-voltage battery components. Defective battery packs can catch fire when overheating or short-circuiting.
From around 100,000–150,000 km front and rear axles on the 508 II show wear on bearings and bushes. Wishbones and anti-roll bar drop links are the most common wear items.
On the 508 R8 owners report play in the steering column and creaking/clicking when turning. Defective steering joints or worn column bearings are typical causes.
The EAT8 automatic gearbox shows too-late or poorly adapted gear changes on some examples. Regular gearbox oil changes per the service schedule reduce the problem considerably.
The touchscreen infotainment regularly shows software faults: inaccurate GPS position, DAB radio drop-outs, Bluetooth connection issues and sporadic screen blackouts.
Defective parking sensors and failed seat heating are among the most common complaints on the 508 II. Moisture ingress into PDC sensors is a typical cause.
The optional infrared night vision camera develops faults after a while. Calibration loss or camera error requires a workshop visit for recalibration.
The leather covering on the steering wheel of the 508 II delaminates on the underside after 30,000–60,000 km. The material detaches at the seams and begins to peel. Typical issue with frequent UV exposure or sweaty hands.
Below 5°C the automatic climate control stops dehumidifying and windows mist up. A BSI software update temporarily resolves the issue. Cut-outs under strong sunlight are also known.
