BMW S62

BMW M's 4.9 V8 — the E39 M5's engine, and the Z8's.

It is an M-division engine and it is not the M62 it is derived from: individual throttle bodies, double-VANOS on both banks, a semi-dry-sump oiling system and a much higher state of tune. Advice written for the ordinary V8 is wrong here more often than it is right.

⚑ The VANOS units are the defining maintenance item, and their failure is gradual rather than sudden: a soft bottom end, a rattle at idle and a check-engine light for cam timing, usually traced to the seals inside the unit. It is a known rebuild rather than a mystery.

The rod bearings are the item that decides an engine's fate, and the pattern is well documented enough that a preventive replacement on a high-mileage car is a normal thing to do rather than a panic. Oil analysis is the cheap way to ask the question.

Its throttle actuators and idle behaviour are electronic and age badly; a hunting idle on one of these is very often the actuator motors rather than a vacuum leak.

Parts are M-specific and priced accordingly, which is usually what decides whether a fault is worth chasing.