Peugeot 508
Most widespread PSA diesel. Went through many evolution stages from Euro 4 to Euro 6. Economical and long-lived with regular servicing. Prone to DPF issues in short-trip operation.
Big estate, small engine
112 hp in the 508 SW is a disappointment. The large estate weighs over 1,500 kg and urgently needs more power.
Engine Weaknesses 6
The 1.6 HDi is notorious for repeated turbocharger failures. Soot particles in the oil alter viscosity, oil lines coke up and the turbocharger runs dry. A second failure after replacement without addressing the root cause is common.
Symptoms: Whistling from the turbocharger, severe power loss, blue or black exhaust smoke, oil leaking from turbo, engine enters limp mode
The copper sealing rings on the injectors wear out, allowing combustion gases and diesel to enter the cylinder head. Oil dilution by diesel can lead to engine damage. Affects all 1.6 HDi variants.
Symptoms: Diesel smell at the dipstick, rising oil level, black deposits around injectors, rough engine running, hissing noises at the cylinder head with engine running
The cam-to-cam timing chain between inlet and exhaust camshafts can stretch or snap. Hydraulic chain tensioners fail, causing valve timing shift and in extreme cases engine damage.
Symptoms: Rattling on cold start, rough engine running, engine management light, power loss, in extreme cases sudden engine shutdown from chain snap
The plastic impeller on the water pump breaks away early and can damage the timing belt or cause engine failure. Engine damage documented from as low as 70,000–88,000 km. Always replace the water pump at the same time as the timing belt.
Symptoms: Engine overheating, timing belt snaps without warning, fan noise, coolant loss
During short-trip use DPF regeneration fails regularly. Deposits in the EGR and throttle body additionally prevent correct regeneration. From 160,000 km complete replacement is frequently needed.
Symptoms: Warning 'particulate filter filling up', noticeable power loss, increased fuel consumption, engine judders under acceleration, limp mode
Leaks around the injector sealing area let exhaust gases into the cylinder head. A gel-like oil residue forms in the head chambers (especially pre-2006 build). Professional cleaning takes around 10 labour hours. Turbo damage threatened by oil contamination.
Symptoms: Turbo damage, power loss, black oil paste around injectors, engine oil contamination
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.
