Citroën C5

The DW12 uses two turbos in a parallel sequential arrangement. The small turbo works alone up to 1,400 rpm; both operate from 2,500 rpm. Seizure or bearing wear in one turbo causes uncontrolled boost pressure. Complex and expensive to repair.

Symptoms: Power loss, whistling/rattling noises, smoke, fault code.

The 2.2 HDi with EOLYS-based FAP is considered particularly susceptible to DPF problems. Lack of motorway driving leads to blockage. Regeneration failure increases oil dilution. Some mechanics fundamentally advise against this engine for short-trip drivers.

Symptoms: FAP warning light, power loss, limp mode, strong fuel smell in oil.

Under high mileage and thermal stress, DW12 cylinder heads can develop cracks. Known among mechanics as a problematic engine. In isolated cases, a complete engine swap from 2.2 to 2.0 HDi has been performed.

Symptoms: Coolant loss, mayonnaise in oil, overheating, white exhaust smoke.

The turbocharger on the DW12 2.2 HDi suffers from oil sludge and contamination that restricts the turbo's oil supply. Shaft play, whistling noises, and eventually bearing seizure are the result. Oil must be changed regularly.

Symptoms: Whistling turbo noise, blue smoke on acceleration, increased oil consumption above 0.5 L/1000 km, power loss. Turbo no longer spins up freely under load.

The crankshaft torsional damper wears at higher mileages. The inner and outer rings begin to slip, leading to rough running, knocking noises, and accessory belt drive problems. Known with heavy use.

Symptoms: Knocking/squealing at idle, belt noise, slightly rough engine running.

The EGR cooler on the DW12 2.2 HDi develops cracks and drips coolant onto hot exhaust parts where it evaporates. No visible external coolant loss. Risk of gradual overheating; coolant must be topped up regularly.

Symptoms: Gradual coolant loss with no visible external leaks, whitish steam from exhaust, cooling system requires frequent topping up, coolant warning light.

The optional Hydractive 3+ suspension (standard on Exclusive trim) in the C5 II starts leaking at spheres and cylinders from around 80,000 km. A 'Suspension defective' message appears and the car limits top speed to 90 km/h.

The electric power steering in the C5 II is connected to the BSI control unit. BSI faults or ECU problems cause the power assistance to fail. A frequently reported issue is sudden loss of assist while the engine is running.

The automatic gearbox in the C5 II (2008–2017) shows typical problems pulling away from standstill. Only after firm throttle input does the gearbox engage properly. A gearbox flush or software update often helps, but solenoids are due at higher mileages.

The 2016 MOT report documents above-average frequency of tie rod wear and increased driveshaft wear on the C5 II. Tyre inner edge wear and clunking in corners are typical symptoms.

According to MOT reports, the C5 II frequently shows oil leaks at engine and gearbox seals as well as occasional BSI control unit problems. Faulty EGR valves cause short-circuit risks at the starter cable connection (recall 2013–2017).