Cooling System: Service and Repair
Coolant, Draining and Filling
Special tools, testers and auxiliary items required
• Adapter (V.A.G 1274/8)
• Adapter for VAG 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)
Draining
- On vehicles with air suspension, activate vehicle lift mode.
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 in the system.
- Open the coolant reservoir cap.
- Remove the front noise insulation - 1 -..
• Collect escaping coolant in a clean container for disposal or reuse.
- Place the (VAS 6208) under the engine.
- Remove the right lower coolant hose - arrow - from the radiator by lifting the clamp and let the coolant drain out.
- Open the clamps - 1 and 2 -, drain the coolant and then remove the coolant hoses from the coolant pipes.
- Open the clamps - arrows -, drain the coolant and remove the coolant hoses from the coolant pipes on the left longitudinal member.
- Open the clamp - 1 -, drain the coolant and remove the coolant hose from the coolant pipe on the lock carrier.
• Ignore - 2 -.
- Remove the coolant hose from the engine oil cooler by loosening the hose clamp - arrow - and letting the coolant drain out.
Filling
Tightening specifications, refer to:
• => [ Coolant Pump and Thermostat Overview ] Coolant Pump and Thermostat Overview
• => [ Coolant Pipes Overview ] Coolant Pipes Overview
• Ignition turned off
• The cooling system is filled year year-round with a mixture of water and coolant additive. Mixture ratio.
• Only use coolant according 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.
• Coolant with the correct mixture ratio prevents freezing and corrosion damage and calcium deposits. They also raise the boiling point. For this reason the system must be filled all year round with frost and corrosion protection additives.
• 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%.
• If for climatic reasons a greater frost protection is required, the amount of protection can be increased, but only up to 60% (frost protection to about -40 °C (-40 °F)), as otherwise frost protection is reduced again and cooling effectiveness is also reduced.
• 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.
• Use the (T10007) to determine the level of freeze protection in the coolant system.
• Secure all hose connections with hose clamps of the same type as those equipped by the factory. Refer to the Parts Catalog.
• Replace the gasket and O-ring.
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 (60%) and water (40%) for freeze protection down to -40 °C (-40 °F)
• For the correct coolant. Refer to the Parts Catalog
Procedure
- Attach the coolant hose and clamp - arrow - to the oil cooler.
- Attach the coolant hose and clamp - 1 - to the coolant pipe on the lock carrier.
- Attach the coolant hoses and clamps - arrows - to the coolant pipes on the left longitudinal member.
- Attach the coolant hoses and clamps - 1 and 2 - to the coolant pipes.
- Attach the coolant hose - arrow - with the right lower decoupling element to the radiator. Refer to => [ Connect the Coolant Hose to the Coupling ] Radiator Overview.
- Fill the coolant reservoir on the (VAS 6096) with at least 15 liters of premixed coolant with the proper mixture ratio.
- Attach the (V.A.G 1274/8) to the 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 the 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 the 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 (V.A.G 1274/8) on the 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 - on the charge air coolers one after the other until coolant starts to come out.
- Close the bleeder screw.
- Open the bleeder screw - arrow - on the left and right coolers for the charge air cooling circuit until coolant starts to come out.
- Close the bleeder screw.
- If the vehicle has an auxiliary heater, switch it on for about 30 seconds.
- Close the coolant reservoir cap.
- Start the engine.
- Set the temperature to "HI" for all zones and set the fan speed (0).
- Press the ECON/ON/OFF button to turn off the A/C compressor.
- 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 1 minutes.
- Turn off the engine and allow it to cool off.
- Install the noise insulation..
- Check the coolant level.
• Coolant level must be at MAX-marking - arrow - with engine cold.
• Coolant level may be above MAX marking with engine at operating temperature.
- On vehicles with air suspension, deactivate vehicle lift mode.