Circulation pump installation details (models 463.250/323, code H12)
3 - Return hose of the cooling tract (heater); 4 - Cooling tract inlet hose; 5 - Heater cover; 8 - Circulation pump wiring connector; 13 - Fastening clamp; 17 - Bolt; A6 - Additional heater STH; A6m1 - Circulation pump
1. Open the expansion tank cap to release the pressure in the cooling system.
2. Remove the STH auxiliary heater assembly (see Section Removal and installation of additional heater STH (with appropriate equipment)).
3. Disconnect the electrical wiring connector (8) of the circulation pump - the connector has an asymmetrical shape, which guarantees the unambiguousness of its connection.
4. Loosen the fastening bolt (17), remove the clamp (13) and dismantle the circulation pump assembly (A6m1), disconnecting it from the supply hose (4).
5. Installation is carried out in reverse order.
6. Finally, bleed the cooling system and check the relevant components for signs of developing leaks, then check that the STH auxiliary heater is functioning properly (see Section Removal and installation of additional heater STH (with appropriate equipment)).
Original source of information MERCEDESMAN