Oil-water heat exchanger removal and installation procedure for Smart Fortwo 454 with 639.939 engine, showing numbered service steps and component callouts.

Service manual page showing heat exchanger removal steps with engine diagram and callout numbers 1-4 for oil-water heat exchanger, oil filter, coolant hose, and screw.

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See all Powertrain figures for the Fortwo / Forfour (453), 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.