Cooling System: Service and Repair
Cooling System, Draining and Filling
Special tools, testers and auxiliary items required
• Adapter (V.A.G 1274/8)
• Drip Tray (VAS 6208)
• Hose Clip Pliers (V.A.G 1921)
• Cooling System Charge Unit (VAS 6096)
• Refractometer (T10007)
Draining
• Collect draining coolant in a clean container for disposal or reuse.
Risk of scalding due to hot steam and hot coolant.
• The coolant system is under pressure when the engine is warm.
• Reduce pressure by covering coolant reservoir cap with a cloth and carefully opening.
- Open the coolant reservoir cap.
- Remove the front noise insulation - 1 -.
- Place the (VAS 6208) under engine.
- Remove coolant hose downward from radiator - arrow - and allow coolant to drain.
- Remove lower coolant hose to after-run coolant pump (V51) - arrow - and allow coolant to drain.
• The illustration shows the coolant hose on a vehicle with an S-Tronic transmission.
Filling
• The cooling system is filled year year-round with a mixture of water and coolant additive. Mixture ratio.
• Only use one of the frost and corrosion additives approved for this vehicle, refer to the electronic parts catalog ETKA. Other coolant additives may above all reduce the corrosion protection effect significantly. The damage resulting from this may lead to loss of coolant and consequently to severe engine damage.
• Coolant with the correct mixture ratio prevents freezing and corrosion damage and calcium deposits. They also raise the boiling point. The cooling system must be filled with coolant additive year-round.
• Because of its high boiling point, the coolant improves engine reliability under heavy loads, particularly in countries with tropical climates.
• Protection against frost must be assured down to approximately -25 °C (-13 °F) (in arctic climatic countries down to approximately -35 °C (-31 °F)).
• The coolant concentration must not be reduced by adding water even in warmer seasons and in warmer countries. Coolant additive portion must be at least 40%.
• If increased freeze protection is needed because of the climate, the amount of G12+ can be increased, but only up to 60% to provide freeze protection to about -40 °C (-40 °F). Otherwise the freeze protection and cooling effectiveness will be reduced.
• Only use clean drinking water for mixing coolant.
• Do not reuse coolant if the radiator, heat exchanger, cylinder head or head seal or cylinder block were replaced.
• Dirty coolant may not be used again.
• Use the refractometer (T10007) to determine the level of freeze protection in the coolant system.
- Connect the coolant hose to the connector on the radiator. Refer to => [ Connect the Coolant Hose with the Connector
on the Radiator. ] Radiator and Coolant Fan Overview.
- Connect coolant hose to after-run coolant pump (V51) - arrow -.
- Fill the coolant reservoir on the (VAS 6096) with at least 10 liters of premixed coolant with the proper mixture ratio.
Coolant Mixture Ratio
• Coolant (40%) and water (60%) for freeze protection down to -25 °C (-13 °F)
• Coolant (50%) and water (50%) for freeze protection down to -35 °C (-31 °F)
• Coolant, refer to the electronic parts catalog ETKA
- Attach the (V.A.G 1274/8) to coolant reservoir.
- Install the (VAS 6096) on (V.A.G 1274/8).
- Place air outlet - 1 - in a small container - 2 -.
• A small amount of coolant which should be collected is drawn off with the discharged air.
- Close valves - A - and - B - by turning lever at a right angle to direction of flow.
- Connect hose - 3 - to compressed air.
• Pressure: 6 to 10 bar pressure.
- Open valve - B - by turning level in direction of flow.
• The suction jet pump generates pressure in the coolant system; indicator on display instrument must move into green area.
- Briefly open valve - A - by turning lever in direction of flow so that hose on (VAS 6096) coolant reservoir fills with coolant.
- Close valve - A - again.
- Leave valve - B - open another 2 minutes.
• More pressure is generated in the coolant system by the suction jet pump; indicator on display instrument must stay in green area.
- Close valve - B -.
• Needle in the display instrument must remain in the green region, then sufficient vacuum in the cooling system is obtained for the upcoming filling.
• If needle stands below the green area, repeat procedure.
• If pressure falls, check coolant system for leaks.
- Remove pressurized air hose.
- Open valve - A -.
• Coolant is extracted from the (VAS 6096) coolant reservoir by pressure in the coolant system and the system is filled.
- Remove the (VAS 6096) from the coolant reservoir.
- Fill coolant up to "max" marking.
- Set the temperature at "HI".
- Press the ECON button to turn off the A/C compressor.
- Start the engine and run it at approximately 1500 RPM for a maximum of 2 minutes.
- With engine running, fill coolant up to overflow hole on coolant expansion tank.
- Close cap on coolant expansion tank.
- Run the engine at idle until both large coolant hoses on the radiator are warm.
- Turn off engine and allow it to cool off.
- Install the noise insulation.
- Check the coolant level.
• The coolant level must be between the "min" and "max" markings when the engine is cold.
• The coolant level may be at the "max" marking when the engine is warm.
- Add more coolant if necessary.