Additional heater installation details (models 463.250/323, code H12)
1 - Outlet hose of the cooling path; 2 - Inlet hose of the cooling path; 3 - Fuel line; 4, 5 - Couplings; 6 - Bandages; 7 - Outlet pipe; 8 - Mounting bolts; A6 - Additional heater block (STH)
1. Jack up the car and put it on stands.
2. Remove the crankcase protection.
3. Empty the cooling system (see chapter Ongoing care and maintenance).
4. Disconnect the inlet (2) and graduation (1) coolant path hoses from STH heater and water pump assemblies.
5. Disconnect from STH heater assembly (A6) fuel line (3), - Prepare to collect spilled fuel.
6. Letting go of bandages (6), disconnect the couplings (4 and 5) electrical wiring, - bandage tapes must be replaced without fail.
7. Disconnect from the STH heater (A6) exhaust pipe (7).
8. Turn out fixing bolts (8) and remove the STH auxiliary heater assembly (A6).
9. Remove the circulation pump (see Section Removal and installation of circulation pump for auxiliary heater STH (with appropriate equipment)).
10. Installation is carried out in the reverse order.
11. Finally, remove air from the cooling system path and check the relevant components for signs of leak development.
12. Start the additional heater and make sure that it is working properly, - if the heater turns off automatically before the coolant temperature reaches the normal operating value and cannot be restarted, therefore, a false lock is triggered in the system, - drive the car to a Mercedes-Benz service station for a detailed diagnostics using the STAR DIAGNOSIS reader (6511 1801 00).