Nissan VK45DE / VK50VE

Nissan's V8 for Infiniti — 4.5 as the VK45DE, 5.0 as the VK50VE — in the Q45, M45, FX45 and FX50. The truck version of the same family is the VK56.

The VK50VE has VVEL and the VK45DE does not, which is the distinction that decides a diagnosis. Variable Valve Event and Lift throttles on the intake valves themselves through an actuator and linkage on each bank; when it fails the engine loses power abruptly and sets a code naming the system, and the assembly is expensive. Nothing about a VK45 prepares you for it, and the same system on the VQ37 is where most of what is written about it lives.

Both are chain-driven, and the chain and its guides are the wear item at high mileage — a rattle at start-up that settles with oil pressure.

Oil consumption climbs late in life, and it matters more on the VK50 than the numbers suggest: VVEL is hydraulically actuated and runs on the engine's oil, so low or degraded oil is a VVEL fault waiting to happen rather than only a maintenance lapse.

The exhaust manifolds crack on high-mileage examples, presenting as a tick that is loudest cold and fades as the metal expands.