Cooling System: Service and Repair
Coolant, Draining and Filling
Special tools, testers and auxiliary items required
• Adapter (V.A.G 1274/8)
• Adapter for V.A.G 1274 tester (V.A.G 1274/10)
• Cooling System Charge Unit (VAS 6096)
• DRIP TRAY FOR VAS 6100 (VAS 6208)
• Hose Clip Pliers (VAS 6362)
• Refractometer (T10007)
• Hose Clip Pliers (VAS 6340)
Draining
• Collect escaping 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.
• Cover the coolant reservoir cap with a cloth and then open it slowly to release the pressure.
- Open the coolant reservoir cap.
- Remove the front noise insulation - 1 -.
- Place the (VAS 6208) under the engine.
- Remove the drain plug - 1 - and drain the coolant.
• Ignore - 2 -.
- Loosen the hose clamp - arrow -, remove the coolant hose from the oil cooler and drain the coolant.
• The engine is not shown in the following illustrations.
Vehicles with Left Front Coolant Pipes, Version 1
- Loosen the hose clamps - 1 and 3 -, remove the left front coolant hoses from the coolant pipes and drain any remaining coolant.
• Ignore - 2 -.
Vehicles with Left Front Coolant Pipes, Version 2
- Loosen the clamps - arrows -, drain any remaining coolant and then remove the coolant hoses from the left front coolant pipes.
• Ignore - 1 -.
Filling
• Ignition turned off
• The cooling system is filled year year-round with a mixture of water and coolant additive.
• Use only the coolant additive approved for this engine. Refer to the Parts Catalog. 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.
• The coolant additive prevents frost and corrosion damage as well as lime deposits. It also raises the boiling temperature. 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. The coolant additive portion must be at least 40%.
• When stronger freeze protection is needed due to the climate, the portion of coolant additive can be increased. It can be increased up to 60% (freeze protection down to -40 °C (-40 °F). If it is increased even more, the freeze protection and cooling effect are decreased.
• Only use clean drinking water for mixing coolant.
• Only reuse drained coolant if the radiator, the heater heat exchanger, cylinder head, cylinder head gasket or cylinder block were not replaced.
• Dirty coolant may not be used again.
• Secure all hose connections with hose clamps of the same type as those equipped by the factory, refer to the Parts Catalog.
• Replace the O-rings for the bleeder screws on the charge air coolers.
• Use the (T10007) to determine the level of freeze protection in the coolant system.
- Close the drain plug - 1 -.
- Install the coolant hose on the engine oil cooler - arrow -.
Vehicles with Left Front Coolant Pipes, Version 1
- Install the coolant hoses - 1 and 3 - to the left front coolant pipes.
Vehicles with Left Front Coolant Pipes, Version 2
- Attach the coolant hoses - arrows - to the left front coolant pipes.
All Vehicles
- Fill the coolant reservoir in the (VAS 6096) with 12 liters of coolant having the correct mixture ratio:
• Coolant additive (40%) and water (60%) for freeze protection down to -25 °C (-13 °F)
• Coolant additive (50%) and water (50%) for freeze protection down to -35 °C (-31 °F)
• For the correct coolant additive, refer to the Parts Catalog.
- Attach (V.A.G 1274/8) to coolant reservoir.
- Install the (VAS 6096) on the (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.
• A further vacuum is created in the cooling system by the suction jet pump. Needle on the instrument display must travel into the green region.
- Briefly open valve - A - by turning lever in direction of flow so that the hose on (VAS 6096) coolant reservoir fills with coolant.
- Close valve - A - again.
- Leave valve - B - open another 2 minutes.
• A further vacuum is created in the cooling system by the suction jet pump. Needle on the instrument display must still remain in the green region.
- Close valve - B -.
• Needle in the display instrument must remain in the green region, then the 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 (VAS 6096) form (V.A.G 1274/8) on coolant reservoir.
- Connect the (V.A.G 1274/10) to the (V.A.G 1274/8).
- Fill the coolant until the coolant system tester tube is full. Fill again during the bleeding procedure if necessary.
- Remove the rear engine cover - 2 - upward.
• Use a cloth to catch any leaking coolant.
- Open the bleeder screws - 1 and 2 - one after the other until coolant starts to come out.
- Close the bleeder screw.
- Remove the seal from the plenum chamber bulkhead.
- Remove the plenum chamber cover.
- Disconnect the heat exchanger coolant hose and pull it back until coolant starts to drain out of the bleed hole - arrow - in the coolant hose.
- Slide the coolant hose onto the connection and secure with a spring clamp.
- If the vehicle has an auxiliary heater, switch it on for about 30 seconds.
- Turn the coolant reservoir cap until it closes completely.
- Start the engine.
- Set the temperature to "HI" for all zones and set the fan speed (0).
- Press the AC button to turn off the Air Conditioning (A/C) compressor.
• The LED in the button must not come on.
- Run the engine at 2000 RPM for 3 minutes.
- Run the engine at idle until both large coolant hoses on the radiator are warm.
- Run the engine at 2000 RPM for 2 minutes.
- Turn off engine and allow it to cool off.
- Install the noise insulation.
- Check the coolant level.
• With the engine cold, coolant level must be at MAX marking.
• Coolant level may be above MAX marking with engine at operating temperature.