Audi Workshop Service and Repair Manuals

Draining and filling cooling system

Special tools and workshop equipment required

t	Adapter for cooling system tester -V.A.G 1274/8-

t	Pipe for cooling system tester -V.A.G 1274/10-

t	Drip tray for workshop hoist -VAS 6208-

t	Cooling system charge unit -VAS 6096-

t	Hose clip pliers -VAS 6362-

t	Refractometer -T10007-

Draining   Note Collect drained coolant in a clean container for re-use or disposal.

WARNING Hot steam or hot coolant can escape when expansion tank is opened; cover filler cap with cloth and open carefully. –  Open filler cap on coolant expansion tank.

–  Vehicles with auxiliary heater: remove bolts -arrows- securing exhaust pipe for auxiliary/additional heater to noise insulation.

–  Release quick-fasteners -1- and -2- and take off front noise insulation. Leave rear noise insulation in position.

–  Place drip tray for workshop hoist -VAS 6208- under engine. Vehicles with coolant drain plug: –  Unscrew the drain plug -arrow- at coolant hose (bottom left) and drain off coolant.

Vehicles without coolant drain plug: –  Pull out retaining clip -1- for coolant temperature sender at radiator outlet -G83--item 2-. –  Pull coolant temperature sender at radiator outlet -G83- out of hose connection and drain off coolant. –  Move wiring for coolant temperature sender at radiator outlet -G83- clear.

All vehicles: –  Unbolt coolant expansion tank -arrow-. –  Unplug electrical connector for coolant shortage indicator switch -F66- at bottom of expansion tank and move expansion tank to one side with coolant hoses -1- and -2- attached.

–  Also disconnect coolant hose at engine oil cooler -arrow- and drain off remaining coolant. Filling   Note t  The cooling system is filled all year round with a mixture of water and coolant additive. Mixture ratio → Anchor. t  Use only the coolant additive listed in the → Electronic parts catalogue. Other coolant additives could seriously impair in particular the anticorrosion properties. The resulting damage could lead to loss of coolant and consequently to serious engine damage. t  The specified coolant (based on recommended mixture ratio) → Anchor prevents frost and corrosion damage and stops scaling. Such additives also raise the boiling point of the coolant. For these reasons the cooling system must be filled all year round with the correct coolant/anticorrosion additive. t  Because of its high boiling point, the coolant improves engine reliability under heavy loads, particularly in countries with tropical climates. t  Frost protection is required down to about –25 °C (in countries with arctic climate: down to about –35 °C). t  The coolant concentration must not be reduced by adding water even in warmer seasons and in warmer countries. The antifreeze concentration must be at least 40 %. t  If greater frost protection is required in very cold climates, the amount of antifreeze can be increased, but only up to 60 % (this gives frost protection to about -40 °C), as otherwise frost protection is reduced again, as is cooling effectiveness. t  Use only clean tap water for mixing coolant. t  Do not use drained coolant again if: t  the radiator, heat exchanger for heater, cylinder head, cylinder head gasket or cylinder block have been renewed. t  the coolant is contaminated or dirty. t  For checking anti-freeze protection in cooling system, use refractometer -T10007-. t  Secure all hose connections with the correct type of hose clips (same as original equipment) → Electronic parts catalogue. Recommended mixture ratio for coolant l  Coolant (40 %) and water (60 %) for frost protection to -25 °C l  Coolant (50 %) and water (50 %) for frost protection to -35 °C l  Coolant (60 %) and water (40 %) for frost protection to -40 °C l  Coolant → Electronic parts catalogue

Vehicles with coolant drain plug: –  Close drain plug -arrow-.

Vehicles without coolant drain plug: –  Insert coolant temperature sender at radiator outlet -G83--item 2- with new O-ring into connection and locate with retaining clip -1-.

All vehicles: –  Connect coolant hose to engine oil cooler -arrow-.

–  Fill reservoir -VAS 6096/1- with at least 10 litres of premixed coolant (according to recommended ratio). –  Screw adapter for cooling system tester -V.A.G 1274/8- onto coolant expansion tank. –  Attach cooling system charge unit -VAS 6096- to adapter -V.A.G 1274/8-. –  Run vent hose -1- into a small container -2-. (The vented air draws along a small amount of coolant, which should be collected.) –  Close the two valves -A- and -B- by setting lever at right angle to direction of flow. –  Connect hose -3- to compressed air. l  Pressure: 6 ... 10 bar.

–  Open valve -B- by setting lever in direction of flow. The suction jet pump generates a partial vacuum in the cooling system. l  The needle on the gauge should move into the green zone. –  Also briefly open valve -A- (turn lever in direction of flow) so that hose on charge unit -VAS 6096/1- can fill with coolant. –  Close valve -A- again. –  Leave valve -B- open for another 2 minutes. l  The suction jet pump will continue generating a vacuum in the cooling system. l  The needle on the gauge should remain in the green zone. –  Close valve -B-. l  The needle on the gauge should stop in the green zone. The vacuum level in the cooling system is then sufficient for subsequent filling. If the needle does not reach the green zone, repeat the process. If the vacuum level drops, there is a leak in the cooling system. –  Detach compressed air hose. –  Open valve -A-. The partial vacuum in the cooling system causes the coolant to be drawn up out of the reservoir; the cooling system is then filled. –  Detach cooling system charge unit -VAS 6096- from expansion tank.

–  Fit pipe for cooling system tester -V.A.G 1274/10- onto adapter for cooling system tester -V.A.G 1274/8-.

–  If fitted, detach rubber seal from plenum chamber cover in direction of -arrow-. –  Detach plenum chamber cover -1- towards the front.

–  Loosen coolant hose going to heat exchanger and pull back hose until bleeder hole in hose -arrow- is no longer blocked by the connection. –  Fill up with coolant until it flows out at bleeder hole in coolant hose. –  Push coolant hose onto connection and secure with hose clip. –  On vehicles with auxiliary heater, switch heater on (for about 30 seconds) and then off again. –  Tighten filler cap on expansion tank. –  Start engine. –  Set temperature to “HI”. –  Switch off air conditioner compressor (press ECON button). l  The LED in the button should light up. –  Run the engine for 3 minutes at 2000 rpm. –  Allow the engine to run at idling speed until the two large coolant hoses at main radiator become warm. –  Run the engine for 1 minute at 2000 rpm. –  Switch off ignition and allow engine to cool down.

–  Check coolant level. l  The coolant level must be at the MAX marking when the engine is cold. l  The coolant level can be above the MAX marking when the engine is warm.