P0016 on Infiniti: How to Diagnose & Fix

The Q50's 2.0t uses the Mercedes-Benz M274 turbocharged four, shared with the C300 and GLC300. The timing chain and the camshaft adjusters (variable valve timing phasers) wear faster than the engine's design life, with problems commonly surfacing somewhere around 80,000 miles and reported as early as 60,000 on neglected cars. The first symptom is a brief metallic rattle on cold start as oil pressure builds and the tensioner takes up slack. Left alone, chain stretch throws off cam timing, sets correlation codes, and in the worst cases the chain skips teeth or breaks, which on this interference engine destroys valves and pistons. Extended oil change intervals and low oil level accelerate the wear.

The VQ37VHR runs three timing chains — a primary and two secondaries — with plastic guides and hydraulic tensioners. The chains stretch and the guides wear, and because the tensioners rely on oil pressure to take up slack, any oil pressure loss or extended change interval accelerates it sharply. The first symptom is a rattle from the front of the engine on cold start that lasts a second or two until pressure builds, progressing to a rattle that persists at idle. Left alone, stretch pushes cam timing out of correlation and sets timing codes; in the worst outcome the chain skips or a guide fragments, and on this interference engine that means bent valves.

The 5.6L VK56VD engine can develop timing chain stretch, particularly when oil changes are neglected. The primary and secondary timing chains elongate over time, causing rough idle, reduced power, and potential engine damage if not addressed.

Nissan issued a large 2026 recall covering VC-Turbo four-cylinder vehicles including the Infiniti QX55, QX50 and Altima. Under certain operating conditions the engine can experience high oil temperatures that degrade lubrication of the crankshaft main bearing and the A-, C- and L-link bearings of the variable-compression mechanism. In the worst case a bearing seizes or a failed bearing breaches the engine block, causing catastrophic engine failure. This is a distinct defect from the previously documented oil-consumption issue. Nissan also announced a VC-Turbo warranty extension. Symptoms often precede failure and out-of-warranty engine replacements have run five figures.