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 for workshop crane (VAS 6208)
• Hose clamp pliers (V.A.G 1921)
• Cooling system charge unit (VAS 6096)
• Refractometer (T10007)
Draining
Risk of scalding due to hot steam and hot coolant.
• When the engine is warm the cooling system is under pressure.
• Reduce pressure by covering coolant reservoir cap with a cloth and carefully opening.
• Secure all hose connections using hose clamps of series production status
• Arrows on coolant pipes and ends of coolant hoses must align when installing.
• Collect draining coolant in a clean container for disposal or reuse.
- On a vehicle with air suspension, activate vehicle lift mode.
Risk of scalding due to hot steam and hot coolant.
• When the engine is warm the cooling system is under pressure.
• Reduce pressure by covering coolant reservoir cap with a cloth and carefully open.
- Open coolant reservoir cap.
- Remove screws and front - 1 - and rear - 2 - noise insulation.
- Place drip tray (VAS 6208) under engine.
- Remove coolant hose from front coolant pipe - arrow - and drain coolant.
With 2 Zone Climate Control
- Remove coolant hoses - 1 and 2 - to heat exchanger from bulkhead.
With 4 Zone Climate Control
- Remove coolant hoses - arrows - from coolant pipes and drain remaining coolant.
Filling
• The cooling system is filled all year round with a mixture of frost and corrosion protection additives and water.
• Only use one of the frost and corrosion additives approved for this vehicle => Electronic 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.
• Frost and corrosion protection additives prevent freezing and corrosion damage and scaling. 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.
• Freeze protection must be assured to about -25° C (in arctic climatic countries to about -35° C).
• 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 increased freeze protection is needed because of the climate, the amount of G12+ can be increased, but only up to 60% (frost protection to about -40° C), otherwise the freeze protection and cooling effectiveness will be reduced.
• Only use clean drinking water for mixing coolant.
• Do not use drained coolant in the following situations:
• If the radiator, oil cooler, heat exchanger, cylinder head, cylinder head seal or cylinder block were replaced.
• If the coolant is contaminated.
• Use refractometer (T10007) to determine the level of freeze protection in the coolant system.
• Secure all hose connections with hose clamps appropriate for the model => Electronic Parts Catalog.
- Attach coolant hose to front coolant pipe - arrow -.
With 2 Zone Climate Control
- Coolant hoses - 1 and 2 - to heat exchanger at bulkhead.
With 4 Zone Climate Control
- Connect coolant hoses to coolant pipes - arrows -.
Continuation for All
- Fill coolant reservoir on (VAS 6096) with at least 12 liters of premixed coolant with proper mixture ratio:
• Coolant (40%) and water (60%) for freeze protection down to -25° C
• Coolant (50%) and water (50%) for freeze protection down to -35° C
• Coolant (60%) and water (40%) for freeze protection down to -40° C
• Coolant: => Electronic Parts Catalog
- Attach adapter (V.A.G 1274/8) to coolant reservoir.
- Install cooling system charge unit (VAS 6096) on adapter (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 positive pressure.
- Open valve - B - by turning level in direction of flow.
• The suction jet pump generates pressure in 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 cooling system charge unit (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 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 cooling system charge unit (VAS 6096) coolant reservoir by pressure in coolant system and system is filled.
- Remove cooling system charge unit (VAS 6096) form adapter (V.A.G 1274/8) on coolant reservoir.
- Close coolant reservoir cap.
- Start engine.
- Adjust temperature for all zones to "HI".
- Switch A/C compressor off by pressing ECON button.
- Run engine at 2000 RPM for 3 minutes.
- Allow engine to run at idle until both large coolant hoses on main cooler are warm.
- Run engine at 2000 RPM for 1 minute.
- Turn off engine and allow it to cool off.
- Check 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 a vehicle with air suspension, deactivate vehicle lift mode.