BMW Timing Chain Replacement Guide: N47, N20, N47 cousins and What the Job Involves
Timing-chain work is a major engine job. This guide covers the BMW engines we see most — N47 diesels and N20 petrols — and how we decide repair versus stop-driving.
Not every rattle is a chain
Pulleys, dual-mass flywheels, injectors and VANOS all rattle. A chain rattle is metallic, often from cold, often from the rear on N47. We confirm with ISTA cam/crank correlation and a listen at Forest Road before anyone orders a kit.
N47 is the labour story
Rear-mounted chain means gearbox separation or engine-out on many variants. Updated kits, guides, tensioner, correct torque. If valves have met pistons, the quote becomes engine repair. See the dedicated N47 chain article for symptoms.
N20 and others
N20 petrol chains and guides are a different layout — still serious, usually more accessible than N47. B-series engines have their own bulletins; we check the VIN. There is no universal “BMW chain price”.
Oil afterwards
Correct Longlife fill and a sensible CBS interval are how you avoid doing this twice. We will not fill a freshly chained N47 with mystery 5W-30.
Quoting honestly
You get a range after inspection, not a website gimmick. If the car should not be driven, we will say so. Hainault bays are booked for these jobs; they are not squeezed between two pad changes.