Venting Cooling System and Checking for Water Leaks

17 00 039 - Venting cooling system and checking for leaks (N73)





Warning!
Danger of scalding!
Open sealing cap only after engine has cooled down.





No vent plugs on radiator and thermostat housing.
Cooling system is vented while it is filled and during subsequent idle operation.

Note:
Before filling, turn on ignition. Set blower to low level. Seat heating controller to maximum temperature. This ensures that the heater valves are fully opened and the auxiliary water pump starts up.
Important: To ensure complete venting, the auxiliary water pump must deliver coolant!

Installation Note:
Use only recommended coolant.
Check cooling system for leaks Component Tests and General Diagnostics.





Perform filling operation slowly.
Pour coolant into expansion tank (1) up to MAX mark.
Start engine and run at idle speed for approx. one minute (cap open). Then adjust coolant level to MAX.
Close cap and run engine up to operating temperature until main thermostat opens. Check cooling circuit and drain plug for leaks.





Caution!
The engine must be cooled down before the coolant level is checked. Coolant temperature must not exceed 30°C. If ambient temperature is above 30°C, allow engine to cool down to ambient temperature at least.
Check coolant level and adjust to MAX.

Note:
Do not fill coolant expansion tank over MAX level as overfilling will cause the coolant to overflow.