Peugeot 508
Powerful PSA diesel for mid-size and SUV applications. Common rail with turbo. Later versions as BlueHDi with SCR cat and AdBlue.
Strong touring estate
163 hp in the 508 SW I: strong diesel estate with generous torque. Convincing even fully loaded.
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
Broken suspension springs are among the most common TÜV/MOT failures on the 508 I. Particularly the rear springs break at their ends and can prevent an MOT pass.
On 508 models from 2011 an insufficiently tightened wiper arm bolt can cause the wiper to stop working in the rain. Affects vehicles from build year 2011.
On diesel models from build years 2013–2014 the fuel filter heater connector can overheat and cause a fuel leak. Fire risk if the seal fails.
The timing chain on the 1.6 THP and VTi petrol engines in the 508 I stretches prematurely through defective chain tensioners and long oil change intervals. In the worst case the chain snaps, causing catastrophic engine damage.
Water enters the boot on the 508 I through leaking tailgate or rear light seals. The spare wheel well gets wet. Damp electronics in the boot can cause consequential damage.
Alongside the known spring failures, shock absorbers and rear axle rubber bushes on the 508 I also wear prematurely. Particularly at higher mileages over 120,000 km rear axle behaviour deteriorates noticeably.
Faulty parking sensors give false warnings or fail completely. The integrated sat-nav crashes regularly and loses position fix.
The blind of the fixed panoramic roof rattles over road imperfections. Additionally, loose interior trim panels in the dashboard and door area cause annoying noises.
The oil level display on the 508 I frequently shows erratic readings even though the actual oil level is fine. The cause is usually a defective oil level sensor in the sump.
