Auxiliary belt replacement: Mini N12, N14, N16, N18 ancil (N12B14A, N12B16A, N14B16A, N14B16C, …)
Step-by-step auxiliary belt replacement for the Mini N12, N14, N16, N18 ancil: 22 steps. What to remove, in what order, and what to check after.
The ancillary drive belt on the MINI N12, N14, N16 and N18 petrol engines (One, Cooper, Cooper S and John Cooper Works) is changed from the right wheel arch. The right front wheel and wheel arch liner come off, then the belt cover. The tensioner is turned clockwise to take the load off the belt and is held with a special tool so the belt can be slipped off. These engines also have a coolant pump driven by a friction wheel, which is pulled out until it catches and secured to the engine so it is clear while the belt is changed. The deciding check comes at the end: once the friction wheel is released and back in contact, the coolant pump must turn freely.
🧭 Before you start
Remove the right front wheel, wheel arch liner and belt cover, turn the tensioner clockwise and lock it with the special tool, pull the coolant pump friction wheel out until it catches and secure it, then remove the belt. Fit the new belt, release the tensioner and the friction wheel, check the coolant pump turns freely, and refit the cover, liner and wheel.
Fits: platform codes COOPER, |, S, JOHN, WORKS, ONE
Don't miss
- Turn the tensioner clockwise to release belt tension and hold it with the special tool.
- Pull out the coolant pump friction wheel until it grabs and secure it to the engine.
- Check the coolant pump rotates freely after the friction wheel is released.
- Check the belt sits correctly on every pulley before refitting the cover.
Written for this job from the workshop steps below · TorqFix editorial.
📐 27 workshop diagrams for N12B14A
Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.
📋 Procedure
Preparation and removal
- Remove the right wheel arch liner
- Remove the ancillary drive belt cover
- Turn the tensioner clockwise to release the belt tension
- Use a special tool:
- Turn the tensioner clockwise
- Remove the special tool
- Coolant pump friction wheel
- Pull out the handle until it grabs
- Secure to the engine
- Remove the ancillary drive belt
Installation and checks
- Refit the ancillary drive belt
- Refit the front right wheel
- Check that the coolant pump can rotate freely
Ask TorqFix about your Mini N12B14A — it answers with the exact sequence for that engine and the workshop drawing for each step. First question is free after a 20-second sign-up, no card.
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Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.
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The story behind TorqFix →Workshop data on this page last updated 20 Sep 2026.