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	Cooling system charge unit -VAS 6096-

t	Drip tray for workshop hoist -VAS 6208-

t	Hose clip pliers -VAS 6362-

t	Refractometer -T10007-

t  Hose clip pliers -VAS 6340- Draining   Note Collect drained coolant in a clean container for re-use or disposal.

WARNING Hot steam/hot coolant can escape - risk of scalding. t  The cooling system is under pressure when the engine is hot. t  To allow pressure to dissipate, cover filler cap on coolant expansion tank with cloth and open carefully. –  Open filler cap on coolant expansion tank.

–  Remove front noise insulation -1- → Rep. gr.66.

–  Place drip tray for workshop hoist -VAS 6208- beneath engine. –  Remove drain plug -1- and drain off coolant.   Note Disregard -item 2-.

–  Release hose clip -arrow-, disconnect coolant hose from engine oil cooler and drain off coolant.   Note For illustration purposes, the installation position is shown in the following illustrations with the engine removed.

Vehicles with coolant pipes (front left) (version 1): –  Release hose clips -1- and -3-, disconnect coolant hoses from coolant pipes (front left) and drain off remaining coolant.   Note Disregard -item 2-.

Vehicles with coolant pipes (front left) (version 2): –  Release hose clips -arrows-, disconnect coolant hoses from coolant pipes (front left) and drain off remaining coolant.   Note Disregard -item 1-. Filling l  Ignition off.   Note t  The cooling system is filled all year round with a mixture of water and coolant additive. t  Use only the coolant additive approved for this engine → Electronic parts catalogue. Other coolant additives could seriously impair in particular the anti-corrosion properties. The resulting damage could lead to loss of coolant and consequently to serious engine damage. t  Coolant additive 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 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 concentration of coolant additive can be increased, but only up to 60% (this gives frost protection to –40 °C). If the concentration exceeds 60%, frost protection decreases again and cooling efficiency is impaired. t  Use only clean tap water for mixing coolant. t  Drained-off coolant must not be used again if the radiator, heat exchanger for heater, cylinder head, cylinder head gasket or cylinder block are renewed. t  Contaminated or dirty coolant must not be used again. t  Secure all hose connections with the correct type of hose clips (same as original equipment) → Electronic parts catalogue. t  Renew O-rings for bleeder screws on charge air coolers. t  For checking anti-freeze protection in cooling system, use refractometer -T10007-.

–  Close drain plug -1-.

–  Connect coolant hose to engine oil cooler -arrow-.

Vehicles with coolant pipes (front left) (version 1): –  Connect coolant hoses -1- and -3- to coolant pipes (front left).

Vehicles with coolant pipes (front left) (version 2): –  Connect coolant hoses -arrows- to coolant pipes (front left).

All vehicles (continued): –  Fill reservoir of cooling system charge unit -VAS 6096- with 12 litres of premixed coolant (according to recommended ratio): l  Coolant additive (40 %) and water (60 %) for frost protection to – 25 °C l  Coolant additive (50 %) and water (50 %) for frost protection to – 35 °C l  Coolant additive → Electronic parts catalogue –  Fit 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-.   Note The vented air draws along a small amount of coolant, which should be collected. –  Close both valves -A- and -B- (turn lever at right angles 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. l  The suction jet pump generates a vacuum in the cooling system. 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 reservoir of -VAS 6096- 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. 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.   Note t  If the needle does not reach the green zone, repeat the process. t  Check cooling system for leaks if the vacuum is not maintained. –  Detach compressed air hose. –  Open valve -A-. l  The vacuum in the cooling system causes the coolant to be drawn out of the reservoir of the cooling system charge unit -VAS 6096-; the cooling system is then filled. –  Detach cooling system charge unit -VAS 6096- from adapter -V.A.G 1274/8- on coolant expansion tank.

–  Attach pipe -V.A.G 1274/10- onto adapter -V.A.G 1274/8-. –  Fill up with coolant until pipe for cooling system tester is filled. If required, add further coolant when performing bleeding procedure.

–  Lift off engine cover panel (rear) -2-.   Note

Place a cloth underneath to catch escaping coolant. –  Open bleeder screws -1- and -2- one after the other until coolant flows out. –  Close bleeder screws.

–  Pull seal off plenum chamber partition panel. –  Remove plenum chamber cover → Rep. gr.50.

–  Release coolant hose going to heat exchanger and pull back hose until coolant flows out at bleeder hole -arrow- in coolant hose. –  Push coolant hose back onto connection and secure with spring-type hose clip. –  On vehicles with auxiliary heater, switch heater on (for about 30 seconds) and then off again. –  Tighten filler cap on expansion tank, making sure it engages. –  Start engine. –  Set temperature to „HI“ for all zones and select lowest blower speed (= 0). –  Switch off air conditioner compressor (press AC button). l  LED in button should not light up. –  Run engine for 3 minutes at 2000 rpm. –  Allow engine to run at idling speed until two large coolant hoses at radiator become warm. –  Run engine for 2 minutes at 2000 rpm. –  Switch off ignition and allow engine to cool down. –  Install noise insulation → Rep. gr.66.

–  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.