Cooling System: Service and Repair
Coolant, Draining and Filling
Special tools, testers and auxiliary items required
• Adapter (V.A.G 1274/8)
• Drip Tray for VAS 6100 (VAS 6208)
• Hose Clip Pliers (V.A.G 1921)
• Cooling System Charge Unit (VAS 6096)
• Refractometer (T10007)
Draining
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 noise insulation.
- Remove the frame for the noise insulation.
- Remove the air guide pipe - 1 and 2 -.
• Drained coolant must be stored in a clean container for disposal or reuse.
- Place the (VAS 6208) under engine.
- Remove the lower coolant hose - 1 - from the radiator and let the coolant drain.
• Ignore - 2 -.
- Remove lower coolant hose to after-run coolant pump (V51) - arrow - and allow coolant to drain.
Filling:
• The cooling system is filled year-round with a mixture of water and coolant additive. Mixture ratio.
• Only use coolant according 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. 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. Coolant additive portion must be at least 40%.
• If more freeze protection is needed due to the climate, increase the amount of coolant additive, but only up to 60% (freeze protection down to -40 °C (-40 °F)). Otherwise the freeze protection and cooling effectiveness will be reduced.
• If the radiator, heat exchanger, cylinder head or head seal or cylinder block were replaced, do not reuse used coolant.
• Dirty coolant may not be used again.
• Use the (T10007) to determine the level of freeze protection in the coolant system.
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)
- Connect the lower coolant hose - 1 - to the radiator.
- Connect coolant hose to after-run coolant pump - arrow -.
- Fill coolant reservoir on (VAS 6096) with 10 liters of premixed coolant with the proper mixture ratio.
- Attach the (V.A.G 1274/8) to the coolant reservoir.
- Install (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 the 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 the display instrument must stay in the 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.
- Check the coolant level.
- Fill coolant up to "max" marking.
- Start engine and run at approximately 1500 RPM for a maximum of 2 minutes.
- With the engine running, fill coolant up to overflow hole on coolant expansion tank.
- Close the cap on the coolant reservoir.
- Start the engine and let it run at approximately 3000 RPM until the coolant fan starts running.
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.
- Check coolant level.
• With warm engine, coolant level must be at "max" marking, with cold engine, between "min" and "max" marking.
- If necessary, fill with coolant again.
- Shut off engine.
Assemble in reverse order of disassembly.
• The hose supports, air guide pipes and hoses must be free of oil and grease before installing.
• Secure all hose connections with hose clamps of the same type as those equipped by the factory. Refer to the Electronic Parts Catalog (ETKA).
• To mount the charge hoses on their connectors securely, spray the bolts on the used clamps with rust remover before installing.