Pour In Coolant & Bleed Cooling System - Ar20.00-D-1142-04SD

ENGINES 642, 646, 651 

Fig 1: Identifying Vacuum-Type Cooling System Filler (285 589 00 21 00)

Courtesy of MERCEDES-BENZ USA

Fig 2: Identifying Tester Cap (639 589 00 91 00)

Courtesy of MERCEDES-BENZ USA

1. Screw on test cap (2) on expansion reservoir (1).
2. Attach the control unit (3) to the test cap (2).
3. Attach Venturi nozzle (9) to control unit (3).
4. Close drain valve (8) and feed valve (7).
   Fig 3: Bleeding Cooling System Using Vacuum-Type Cooling System Filler (285 589 00 21 00) - Shown on engine 646.985

   Courtesy of MERCEDES-BENZ USA
5. Attach feed hose (4) to coolant reservoir (4a).

   To prevent air from being drawn in, ensure that the coolant tank (4a) contains more coolant than the maximum filling capacity of the cooling system.

6. Guide waste air hose (5) into an empty container (5a)
7. Connect compressed air hose (6) to venturi nozzle (9) and apply pressure.
8. Open drain valve (8).

   A vacuum is created in the cooling system.

9. Open feed valve (7) until feed hose (4) has filled with coolant.
10. Close drain valve (8) if the display of the control unit (3) is in the green area.
11. Detach compressed air hose (6) from the venturi nozzle (9) and monitor if the vacuum remains stable for 30 seconds.

    If this is not the case, check hoses and connections, repair if necessary and check again.

12. Open feed valve (7).

    The cooling system is filled.

13. Open drain valve (8) if coolant is no longer suctioned.
14. Remove the control unit (3) along with all the connections and the test cap (2).
15. Fill coolant up to the bottom edge of the marking on the expansion reservoir (1)