Crankshaft
Turns the pistons’ back-and-forth motion into rotation.
Low in the engine block, supported by main bearings.
Offset journals accept connecting-rod force; counterweights help manage rotating and reciprocating loads.
A bicycle crank converting leg movement into a turning chainring.
Low oil pressure, knocking or abnormal vibration can have several causes around the crank assembly.
Usually condition-based rather than a routine replacement. Lubrication, overheating and the exact engine affect wear.
Internal-engine work is usually labor-intensive. Diagnosis and the engine code determine the repair scope.
BMW’s inline-six layout is known for favorable inherent balance, but it still needs a sound crank and mounting system.
BMW petrol and diesel engines; petrol-only systems are identified individually.