KNOWN FAULT · BMW

S55 crank hub

Sources are not verified in real time and no entry confirms that your car is affected.

Engine / equipment: S55 3.0 twin-turbo (M3 F80, M4 F82/F83, M2 Competition and CS F87)
Period mentioned: 2014–2021
Symptoms: Engine or drivetrain warning, rough running, or the engine cranks but won't start because the ECU blocks it after detecting timing deviation.
Possible cause described: The crank hub that drives the chain is held only by friction from one bolt, with no key. Under high load (aggressive high-rev downshifts or extra power from tuning) it can slip and throw the timing out, risking valve-to-piston contact. It is more common on modified cars.
Check for the garage: Read camshaft deviation with a diagnostic tool and check whether the hub has moved. The permanent fix is a pinned or keyed hub.
Cost cited in the source: Pinned hub: approx. €900–1,000 plus labour; repair after a slip: approx. €750–2,300 (converted from dollars)A rough figure from the original database, not an up-to-date quote.

Sources from the original database

Anonymous answer, no personal data.

How much does it cost to repair this fault?

Pinned hub: approx. €900–1,000 plus labour; repair after a slip: approx. €750–2,300 (converted from dollars)

A rough figure from the original database, not an up-to-date quote.

How is it checked?

Read camshaft deviation with a diagnostic tool and check whether the hub has moved. The permanent fix is a pinned or keyed hub.

What are the symptoms?

Engine or drivetrain warning, rough running, or the engine cranks but won't start because the ECU blocks it after detecting timing deviation.

Which cars and years does it affect?

Brands: BMW
Engine / equipment: S55 3.0 twin-turbo (M3 F80, M4 F82/F83, M2 Competition and CS F87)
Period mentioned: 2014–2021

Find garages near you and, before you say yes, check whether the quote is reasonable.

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