Draining and Filling Coolant

Draining and filling in coolant (includes: bleeding)







Special tools





Components of the radiator, vacuum, filler device


Draining coolant

Caution! Danger of scalding!
Coolants can be extremely hot and pressurized.
Wear suitable protective equipment.
Carefully open the cap on the expansion tank.

1. Position the vehicle at the take-up points provided on a lifting platform.





2. Open rear luggage compartment. Protect the trunk floor panel against soiling with a suitable cover.





3. Open tank cap on the expansion tank and remove.





4. Remove the entire underbody cover.





5. Drain cooling system. Remove the drain plug from the engine, drain the coolant into a container and dispose of coolant according to the country-specific legal requirements if no longer required.





6. Pull the radiator supply and return lines off the engine. To do so, undo the hose clamps, carefully pull off the hoses and allow the remaining coolant to run out. Then clean the inside and outside of the hoses, connect the hoses again and tighten the hose clamps. Check whether the hoses are securely seated.





7. Open the heating lines on the vehicle floor. To do so, open the hose clamp, pull off the lines and drain. Then clean the inside and outside of the hoses, connect the hoses again and tighten the hose clamps. Install the hose clamps and check that the lines are seated correctly.





8. Install drain plug on the engine with a new sealing ring and tighten. Tightening torque: 10 to 15 Nm (7.5 to 11 ft. lbs.).


Filling cooling system (includes bleeding)

1. Screw lid adapter for coolant expansion tank (K 22) onto the expansion tank.

2. Connect the flexible extension (Fz 100) to the lid.





3. Connect the vacuum pressure gauge of the bleeder tool to the flexible extension. When doing so, ensure that both shutoff valves are closed (positioned 90° to flow direction)





4. Connect the Venturi nozzle onto the vacuum pressure gauge.

Note!
^ The radiator cleaning amount which is prepared must be approximately 2 liters more than the amount which has to be filled.
^ An anti-freeze content of -35°C corresponds to a mixture of 50:50 (anti-freeze protection: Water).

5. Place a canister with a sufficient amount of coolant and with an anti-freeze content of -35°C at rear of vehicle near to the expansion tank.





6. Push the filler hose (5) of the vacuum pressure gauge into the canister until the canister floor; guide the return line (6) of the Venturi nozzle into the open.

Note! A hissing sound after connecting the compressed air supply is usual.





7. Connect compressed air supply.





8. Open both shutoff valves on the vacuum pressure gauge until the transparent filler hose has completely filled with coolant.





9. Close the left shutoff valve (V1) on the vacuum pressure gauge and build up vacuum in the coolant circuit.

Note!
^ If a vacuum does not build up, there is a leaking valve in the coolant circuit.
^ Deformation of the rubber hose of the cooling system is normal.
^ If the indicator of the pressure gauge is in the green area of the display scale, enough vacuum has been built up.
^ After both shutoff valves on the vacuum pressure gauge have been closed and the compressed air supply has been unplugged, the vacuum must not drop. If the vacuum drops within approximately 30 seconds, there is a leaking point in the coolant circuit.

10. When there is enough vacuum in the cooling system, close the right shutoff valve (V2) and subsequently unplug the compressed air supply.





11. Reopen the left shutoff valve (V1) on the compressed air pressure gauge. The cooling system will now be filled. This procedure will take approximately 5 minutes.





12. When there is no trace of vacuum present or the coolant is no longer suctioned from the canister, open the right shutoff valve (V2).

13. Subsequently remove the complete filling tool (including the lid K 22).





14. If necessary, fill the coolant expansion tank with coolant up to the maximum marking and screw the lid back on the cap of the expansion tank.





15. Completely reinstall the underside panel.

16. Conduct a test drive with the vehicle and check the fluid level in the expansion tank after the coolant circuit has cooled again and if necessary fill up to the maximum marking with coolant.