Peugeot 508
Top-of-the-range PSA diesel family unit. Powerful and comfortable, but rare on the used car market. More involved servicing than smaller HDi units.
Power saloon
204 hp in the 508 I: the large 2.2 HDi drives the elegant saloon forward convincingly. Real long-distance pleasure.
Engine Weaknesses 6
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
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
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
The plastic actuator housing for the intake manifold swirl flaps breaks over time. Carbon deposits from the EGR system cause the flaps to stick, leading to power loss and uneven combustion.
Symptoms: Power loss at low revs, hesitant acceleration, engine management light, increased fuel consumption
The DW12 is considered more DPF-sensitive than other PSA diesel engines. The filter clogs especially quickly with short-trip and city driving. Regular motorway runs for DPF regeneration are absolutely necessary.
Symptoms: DPF warning, idle problems, engine warning light, power loss in city traffic
The DW12 2.2 HDi is prone to oil loss and problems with the swirl flaps in the intake manifold. Regular diesel additive use helps reduce carbon deposits.
Symptoms: Oil loss without clearly locatable source, swirl flap warning messages, slight power loss
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.
