Poly-V-belt routing diagram for smart 451 engine showing alternator, coolant pump, crankshaft, and tensioner pulleys.

Engine bay photo with numbered callouts identifying belt routing components and pulleys

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See all Powertrain figures for the Fortwo (450), or browse the full figure library. Part numbers and callouts are community-sourced and cross-referenced against the manuals — confirm with your VIN before ordering.