17 00 039 Venting and filling cooling system with vacuum filling unit (N74): Prerequisites
- Cooling system expansion tank must be empty.
- There must be sufficiently premixed coolant in the filling unit container, 1 - 2 liters more than the vehicle filling capacity.
- Use only recommended COOLANT .
- Observe mixture ratio: 50% antifreeze and 50% water. In severely cold areas, the antifreeze can be increased to 60% which provides freezing protection down to-62°F (-52°C). Do not exceed a 60% ratio of antifreeze.
- Observe FILLING CAPACITIES .
- Position the filling unit container at the same height as the coolant expansion tank.
- Compressed air connection with 6 bar pressure present.
- Set heating to maximum temperature.
Use
Connect filling unit (1) with adapter (2) 17 0 113 to coolant expansion tank.
Shutoff valves (A) and (B) must be closed.
Connect venturi nozzle (1) to filling unit (2).
Connect compressed air (1) and open shutoff valve (B).
The venturi nozzle produces a flow noise.
Then open shutoff valve (A) until the filling hose (1) is free of bubbles. Close shutoff valve (A) again. The filling hose (1) is vented in this way.
Shutoff valve (B) remains open (approx. 1 min). Generate vacuum in cooling circuit. The end vacuum is reached at a vacuum of -0.7 to - 0.95 bar. Green scale on the vacuum meter.
Then close shutoff valve (B) again.
Both shutoff valves (A) and (B) must be closed. Then seal Venturi nozzle (1).
The cooling system must hold the vacuum for 30 s. If the needle in the vacuum meter falls, this indicates a leak in the cooling system.
If the vacuum remains constant, proceed with filling.
In the event of leaks, check COOLING SYSTEM FOR LEAKS .
Position the filling unit container at the same height as the coolant expansion tank.
Shut-off valve (B) remains closed during the filling process.
To fill the cooling system, open shutoff valve (A) to filling unit container.
Coolant is now added.
The filling procedure is finished when the needle in the vacuum meter is at 0 bar or no longer falls.
If necessary, reduce remaining vacuum. Open shutoff valve (B) to do so.
Remove filling unit with adapter from expansion tank.
After the cooling system has been filled with the vacuum filling unit, another bleeding procedure must be performed!
Bleeding procedure for vehicles up to 03/2010 (heating pump in heater feed hose) .
- Add coolant up to top edge of the coolant filler neck. Coolant level must not drop any further (no drop in coolant for approx. 1 minute).
- Connect the battery charger and switch on the ignition.
- Set heater to maximum temperature. Press Automatic button (if present) and turn blower down to lowest stage (for a minimum period of 5 minutes).
- Check coolant level and add coolant, if necessary.
- After switching off the heating pump, set the heating to min. temperature and switch off the blower.
- Check cooling system for leaks.
- Close coolant filler neck.
- Start engine and run for approx. 1 min in high idle; to do so, switch on the air conditioning.
- Afterwards, press on accelerator three times for 5 seconds each to approximately 4, 000 RPM. Then leave the vehicle in idle for another approx. 5 minutes.
- Warm up the engine and activate the map thermostat through the diagnosis system.
- When the engine has cooled off, check the coolant level and adjust it to approx. 110 mm to 160 mm below the upper edge of the coolant filler neck (described further below in these instructions).
Bleeding procedure for vehicles from 03/2010 (heating pump in heater return hose) .
- Add coolant up to upper edge of coolant filler neck. Coolant must not drop any further (no drop in coolant for approx. 1 minute.)
- Connect the battery charger and switch on the ignition.
- Check coolant level and add coolant, if necessary.
- Check cooling system for leaks.
- Close coolant filler neck.
- Set heater to maximum temperature. Press Automatic button (if present) and turn blower down to lowest stage (for a minimum period of 5 minutes).
- Start engine and run at increased idle for approximately 1 minute.
- During this period of time, press on accelerator three times for 5 seconds each to approximately 4000 RPM. Then leave the vehicle in idle for another approx. 5 minutes.
- Warm up the engine and activate the map thermostat through the diagnosis system.
- When the engine has cooled off, check the coolant level and adjust it to approx. 110 mm to 160 mm below the upper edge of the coolant filler neck (described further below in these instructions).
When the engine has cooled off, check the coolant level and adjust it to approx. 110 mm to 160 mm below the upper edge of the coolant filler neck (described further below in these instructions). Use a tape measure where appropriate.
Close coolant expansion tank.
Installation note:
Close the sealing cap (1) until the arrows line up.
Check function of cooling system.
Check COOLING SYSTEM FOR LEAKS .