Filling The Cooling System (Includes Bleeding)
WARNING: This page is about a different variant/trim than selected.
Information
- The amount of coolant available must be approx. 2 litres more than the amount to be filled in.
- Because different quantities of coolant can drain away during different types of repairs, the filling capacity can vary greatly. Recommendation: To be on the safe side, fill the canister to 30 l, then bleed the cooling system. The difference after bleeding is the coolant quantity that is sucked in. Check the volume scale on the canister.
- An antifreeze content of -35°C corresponds to a mixture of 50: 50 (antifreeze: water).
Information
- Because different quantities of coolant can drain away during different types of repairs, the filling capacity can vary greatly.
- To be on the safe side, always fill the canister with more coolant than was drained.
- The amount of coolant that was actually added can then be read off the volume scale on the canister.
- An antifreeze content of -35°C corresponds to a mixture ratio of 50: 50 (antifreeze: water).
Information
- The filling process is completed more quickly if the canister is positioned at roughly the same height as the coolant reservoir.
Information
- A hissing sound after connecting the compressed air supply is usual.
Information
- If no vacuum is generated (the pointer does not move to the green area), there is a leak in the cooling system.
- If a vacuum is still not established, there is a blockage in the tool. Clean the device, use clean compressed air.
- Deformation of the rubber hoses of the cooling system is normal.
- Pressure of between 6 and 10 bar must be present. The higher the pressure, the better the vacuum in the vehicle cooling system.
- When the pressure gauge pointer is in the green area of the display scale, a sufficient vacuum has been built up.
- After both shutoff valves on the vacuum pressure gauge have been closed and the compressed air supply has been disconnected, the vacuum must not drop. If the vacuum drops within approx. 30 seconds, there is a leak in the coolant circuit.
Illustration of vacuum-filling device setup
| 1 | Return lines |
| 2 | Overflow container (bucket or canister) |
| 3 | Compressed air connection |
| 4 | Compressed air connection (Pressure of between 6 and 10 bar must be present. The higher the pressure, the better the vacuum in the vehicle cooling system.) |
| 5 | Filling canister with coolant (It is best to position the canister higher than the reservoir). |
| 6 | Adapter K 65 (Fitted instead of the cap of the coolant reservoir.) General illustration provided here. Use an intermediate cable/extension (FZ 100). |
| 7 | KVB 01 (Vacuum gauge with two shut-off valves V1 and V2) |
| V1 | Shut-off valve V1 (Shut-off valve for the filler hose.) |
| V2 | Shut-off valve V2 (Shut-off valve for the filler hose - outlet to Venturi nozzle.) |
- If you have not already done so, screw cap adapter K65 for coolant expansion tank onto the reservoir.
- Connect the flexible extension (FZ 100) to the cap.
- Connect the vacuum gauge of the bleeder tool to the flexible extension. When doing so, make sure that both shut-off valves are closed (positioned at 90° with respect to flow direction).
- Connect the Venturi nozzle to the vacuum gauge. > Connecting Venturi nozzle to vacuum gauge
Connecting Venturi nozzle to vacuum gauge
- Place a canister with a sufficient amount of coolant and with an antifreeze content of -35°C beside the vehicle close to the reservoir.
- Push the filler hose -5-
of the vacuum pressure gauge onto the canister connection. Route the return line -6-
from the Venturi nozzle to a second container (bucket).
Components of vacuum-filling device
- Connect compressed air supply.
Connecting compressed air supply
- Open both shut-off valves on the vacuum gauge > Shut-off valves on vacuum gauge
until the transparent filler hose has completely filled with coolant.
Shut-off valves on vacuum gauge
- Close the left shutoff valve (V1) -Arrow -
on the vacuum gauge and allow a vacuum to build up in the coolant circuit.
Closing left shut-off valve (V1)
- When there is a sufficient vacuum in the cooling system (pointer is in the green area), close the right shut-off valve (V2) and then disconnect the compressed air supply.
Closing right shut-off valve (V2) when there is a sufficient vacuum
- Open the left shut-off valve (V1) on the vacuum gauge again. The cooling system is then filled.
- When there is no vacuum whatsoever present or when coolant is no longer drawn from the canister, open the right shut-off valve (V2). > Opening right shut-off valve
Opening right shut-off valve
- Then remove the complete filling tool (including the K65 adapter).
- If necessary, fill the coolant reservoir with coolant up to the maximum marking.
Coolant reservoir
- Start the engine and allow to run at idle speed. Move the selector lever to position "P" and allow the engine to warm up.
- Switch on passenger compartment heating. Blower setting: one bar.
- Press the "Sport" button. Leave "Sport" mode activated during the bleeding process.
- Check the following while the vehicle is warming up.
- 18.1 Coolant temperature -2-
and engine oil temperature -1-
in the instrument cluster. Figure shows normal, OK values.
Checking temperature on instrument cluster (shown as an example in illustration)
- 18.2 Feel the supply and return coolant hoses for the radiator and the peripheral engine cooling hoses to check that they are heating up uniformly.
- 18.3 It should be possible to force any suspected air bubbles through the cooling system by pressing the accelerator pedal from idle speed to approx. 3500 rpm -3-
during the warm-up phase. Never supply power to the map-controlled thermostat using the workshop tester.
Revs on the rev counter (shown as an example)
- 18.4 The cooling system has been filled and bled correctly if =>
- All coolant hoses are uniformly warm.
- The temperature display in the instrument cluster is in the normal range.
- The passenger compartment heater is warm.
- The electric fan for engine cooling comes on.
- 18.1 Coolant temperature -2-
and engine oil temperature -1-
in the instrument cluster. Figure shows normal, OK values.
- Fit cap on the coolant reservoir.
- Close the service clip on the bleeder valve assembly.
- Close the maintenance cover.