2018 Peugeot 308 1.5L Diesel · UK04 SJS

The 1.2 PureTech three-cylinder petrol engine utilises a wet timing belt operating submerged in engine oil. Fuel contamination and thermal stress cause belt rubber to degrade, shedding fibrous particles into the engine sump. These particles block the oil pump strainer, causing severe oil starvation, vacuum pump failure, and loss of assisted braking (UK recall R/2020/331), with catastrophic engine failure if unaddressed.

BlueHDi diesel engines (1.6 and 1.5 variants) utilize an integrated AdBlue tank assembly housing the urea delivery pump, heater, and level sensor. Urea crystallisation and circuit board failure cause delivery failure, illuminating the UREA warning lamp and initiating a non-restart countdown (commencing at 700 miles). Because the tank is a factory-sealed unit, replacement of the complete tank is required.

The 1.5-litre BlueHDi (DV5R) 16-valve engine introduced in late 2017 uses a 7mm chain connecting the twin overhead camshafts. The chain is prone to excessive wear and stretching, producing metallic rattle before snapping suddenly. Chain failure bends valves, cracks camshaft carriers, and destroys the cylinder head. Stellantis introduced an 8mm upgraded chain kit and revised cylinder head housing to resolve the defect.