Timing chain stretching and tensioner wear causing rough running and misfires
SeriousEngineThe timing chains fitted to the Primera P12 engines (notably the 1.8 petrol QG18DE, 2.0 petrol QR20DE, and 2.2 dCi YD22) are prone to premature elongation and guide wear, especially when subjected to extended oil service intervals. As the chain links wear, the hydraulic tensioner extends to its mechanical limit, allowing slack that disrupts camshaft-to-crankshaft synchronisation. This manifests as metallic cold-start rattling, hesitation under load, rough idling, and engine management warning lights with cam/crank correlation fault codes (P0340/P0335). If left unaddressed, the chain can jump teeth, causing catastrophic valve-to-piston contact on interference engines.
Audible metallic clattering or rattling from the timing cover on the left side of the engine during cold start, Engine hesitation, flat spots under acceleration, and uneven or lumpy idle speed, Engine management light (MIL) illuminated with diagnostic trouble codes P0340, P0335 or P0011, Extended cranking times or engine cutting out unexpectedly when slowing to a junction
- Start the engine from completely stone cold and listen intently near the timing cover for rattling that quietens as oil pressure builds
- Check maintenance documentation for frequent engine oil and filter changes every 6,000 to 9,000 miles
- Scan the engine control unit for stored or pending camshaft and crankshaft timing correlation error codes
- Have a mechanic remove the tensioner inspection access cover to check how far the tensioner plunger has extended