Cooling System, Flushing: Notes
The cooling system must be flushed if the following abnormalities occur:
- The coolant has either developed a more intense color or become discolored.
- The coolant has an unnatural or unusual odor.
- Particles are visible in the coolant.
- Strong deposits have accumulated in the coolant expansion tank.
Coolant has drained from flushing. Then the cooling system is filled with distilled water.
The cooling system is then flushed with approximately 19 liters of distilled water. Afterward the distilled water is replaced with coolant (mixture ratio of 50: 50).
Used coolant cannot be used again.
Brief instructions can be found here. Refer to QUICK REFERENCE GUIDE FOR FLUSHING COOLING SYSTEM . Only the essential procedural steps are listed in the quick reference guide. The brief instructions can be printed and checked off during the procedure.
Special tools and workshop equipment required
- Coolant Flushing and Filling Device: VAS 531 007
- Cooling System Tester - Directional Valve: VAS 691 005/5
- Hose Clip Pliers: VAS 6362
- Shop Crane - Drip Tray: VAS 6208
- Suction jet pump from the Cooling System Charge Kit: VAS 6096
- Refractometer: T10007 A
- Compressed air connector with 6 to 10 bar (87.02 to 145.04 psi) pressure
- Elbow Assembly Tool: T10118
Schematic Overview - Coolant Flushing and Filling Device: VAS 531 007 :
- Reservoir with Distilled Water
- Fill with 30 liters of distilled water
- From this 19 liters will be required for flushing
- 11 liters serve as security reserve and remain in the canister
- Reservoir with Coolant
- Fill with 30 liters of coolant
- Freeze protection through approximately -36 °C (-32.8 °F), (mixture ratio 50: 50)
- From this 18 liters will be required for flushing
- 12 liters serve as security reserve and remain in the canister
- Empty Container
- For used coolant
- Empty Container
- For used coolant
- Suction Hose
- Comes from the connection 2 on the viewing glass
- Viewing Glass
- If colored the viewing glass must be cleaned with a nylon brush
- Pump
- Cut-off pressure approximately 1.5 bar (21.76 psi)
- Valve Block
- With pressure gauge and shut-off valves
- Drain Hose
- Is connected to the valve block to reduce the pressure
- Flushing Hoses
- Is connected for flushing on the coolant expansion tank bleeder hose
- Comes from the connection 1 on the viewing glass
- If not used seal with plugs
- Plugs
- Hose Clamps
- Quantity: 4
- Cleaning Adapters
- Approximately 15 cm (5.91 in.) long
- For cleaning the Coolant Flushing and Filling Device: VAS 531 007 after flushing
- Is connected between the valve block and the flushing hose Flushing Hoses
- Extraction Adapter
- Approximately 100 cm (39.37 in.) long
- Is connected to the suction hose Suction Hose in order to extract the coolant
Procedure:
-- Remove the engine cover. Refer to ENGINE COVER, REMOVING AND INSTALLING .
-- Drain the coolant. Refer to COOLANT, DRAINING AND FILLING .
-- With the coolant hose removed, pour approximately one liter distilled water in the coolant expansion tank.
-- Allow the coolant to drain into the Drip Tray.
-- Reconnect the removed coolant hoses.
Coolant Flushing and Filling Device: VAS 531 007 , Preparing:
-- Fill the container >>1<< with 30 liters of distilled water.
-- Fill the container >>2<< with 30 liters of coolant. Mixture ratio 50: 50 approximately -36 °C (-32.8 °F).
-- Drain the containers >>3<< and >>4<<.
-- Remove the valve block from the connector coupling on the equipment trolley,
-- Connect the Coolant Flushing and Filling Device: VAS 531 007 to the battery.
Coolant Flushing and Filling Device: VAS 531 007 , Bleeding:
-- Connect the suction hose -A- to the reservoir >>1<< with distilled water.
-- Connect the drain hose -arrow- on the connector coupling -B- on the valve block.
-- Close the shut-off valves -A and B-.
Do not connect the valve block to the Cooling System Tester - Directional Valve: VAS 691 005/5 yet. The filling hose must first be bled.
-- Switch on the pump for the Coolant Flushing and Filling Device: VAS531007 .
-- Open the shut-off valve -A-.
-- Briefly open the shut-off valve -B- so that the filling hose is bled.
-- Close the shut-off valves -A and B- again.
Coolant Flushing and Filling Device: VAS 531 007 , Connecting:
-- Open the coolant reservoir cap -arrow-.
-- Install the test adapter -2- (Cooling System Tester - Directional Valve: VAS691005/5 ) on the coolant expansion tank -1-.
-- Remove the drain hose -arrow- from the connector coupling -B- on the valve block.
-- Connect the valve block -1- on the test adapter -2-.
-- Connect the suction jet pump -2- from the Cooling System Charge Kit: VAS6096 to the connector coupling -B- on the valve block -1-.
Cooling System, Filling with Distilled Water
-- Place the drain hose -8- from the suction jet pump in a container.
-- Connect the pressure hose -6- on the suction jet pump -7-.
-- Open the shut-off valve -B- on the valve block -5-.
- A further vacuum is created in the cooling system by the suction jet pump. The needle on the pressure gauge must lower to a minimum - 0.85 bar (-12.33 psi).
-- Close the shut-off valve -B-.
-- Remove the pressure hose -6-.
-- Watch the pressure gauge. The needle on the pressure gauge must stay at a minimum - 0.85 bar (-12.33 psi). Only then is there enough vacuum in the coolant system for the filling.
Check the cooling system for leaks if the pressure drops.
The vacuum required depends on the pressure in the pressure air system.
-- >>Slowly<< open the shut-off valve -A-.
- The distilled water is extracted and the cooling system is filled via the vacuum in the cooling system. The pump for the Coolant Flushing and Filling Device: VAS531007 also moves the distilled water into the coolant expansion tank.
-- Fill the cooling system until approximately 1 bar (14.5 psi) pressure is displayed.
After filling, the coolant expansion tank must be depressurized. Proceed as follows:
-- Close after filling the shut-off valve -A-.
-- Remove the suction jet pump -2- from the valve block -1-.
-- Connect the drain hose -arrow- to the connector coupling. Open the shut-off valve -B- and leave it open, so that the pressure in the cooling system reduces.
-- Remove the air filter housing. Refer to AIR FILTER HOUSING, REMOVING AND INSTALLING .
-- Release and disconnect the connector -1- from the Engine Coolant Temperature Sensor -G62- -3- with the ignition switched off.
When the connector is disconnected from the Engine Coolant Temperature Sensor -G62-, the Engine Temperature Control Actuator -N493- is opened when the engine starts and the radiator fan runs.
-- Temporarily install the air filter housing so that the space on the cylinder head remains accessible. The air filter housing can for example be laid on the battery.
-- Start the engine and let it run for one minute with increased speed. Then switch off the engine.
Cooling System, Flushing with Distilled Water
- Shut-off valve -A- closed, and shut-off valve -B- opened.
-- Remove the bleeder hose -2- from the coolant expansion tank -1-.
-- Connect the bleeder hose -2- from the coolant expansion tank with the flushing hose -1-.
-- Seal the connection on the coolant expansion tank using the plugs -3-. Secure the plug with a hose clamp.
-- Close the shut-off valve -B-.
The cooling system will be flushed. Pay attention to the fill level of the reservoir to maintain the flushing volume.
The engine runs at idle during the entire flushing procedure.
-- Start the engine and let it run in idle.
-- Set the heater temperature to "HI".
-- Press the AC button to turn off the A/C compressor.