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	Drip tray for workshop hoist -VAS 6208-

t	Hose clip pliers -V.A.G 1921-

t	Cooling system charge unit -VAS 6096- with -VAS 6096/1-

t	Refractometer -T10007-

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  Cover filler cap on coolant expansion tank with a cloth and open carefully to dissipate pressure. –  Open filler cap on coolant expansion tank.

–  Remove centre noise insulation -fasteners 1 ... 3-.

–  Place drip tray for workshop hoist -VAS 6208- under engine. Vehicles with drain plug: –  Turn drain plug -arrow- on radiator anti-clockwise, if necessary fit drain hose to connection. Vehicles without drain plug: –  Remove bottom coolant hose -2- from radiator by pulling off retaining clip.   Note Disregard -item 1-. All vehicles (continued): –  Drain cooling system.

–  In addition, remove lower coolant hose to continued circulation coolant pump -V51--arrow- and drain off remaining coolant. Filling   Note t  The cooling system is filled all year round with a mixture of water and radiator antifreeze/anti-corrosion agent. t  Use only the radiator antifreeze/anti-corrosion agent approved for this engine → 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 radiator antifreeze/anti-corrosion agent 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 antifreeze and 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 coolant concentration must be at least 40 %. t  If greater frost protection is required in very cold climates, the concentration of radiator antifreeze/anti-corrosion agent can be increased, but only up to 60% (this gives frost protection to about –40 °C). If the concentration exceeds 60%, frost protection decreases again and cooling efficiency is also impaired. t  Use only clean tap water for mixing coolant. t  If radiator, heat exchanger, cylinder head, cylinder head gasket or cylinder block have been renewed, do not re-use old coolant. t  Contaminated or dirty coolant must not be used again. t  For checking anti-freeze protection in cooling system, use refractometer -T10007-.

Vehicles with drain plug: –  Close drain plug -arrow-. Vehicles without drain plug: –  Connect coolant hose to lower part of radiator -2-.   Note Disregard -item 1-. All vehicles (continued):

–  Connect coolant hose to continued circulation coolant pump -V51--arrow-.   Note Illustration shows vehicle with direct shift gearbox.

–  Fill reservoir -VAS 6096/1- with at least 10 litres of premixed coolant (based on recommended ratio): l  “G12+” (40 %) and water (60 %) for frost protection to –25°C l  “G12+” (50 %) and water (50 %) for frost protection to –35°C l  “G12+” (60 %) and water (40 %) for frost protection to –40°C –  Screw adapter for cooling system tester -V.A.G 1274/8- onto coolant expansion tank. –  Attach cooling system charge unit -VAS 6096- onto 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 reservoir -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 -VAS 6096/1-; the cooling system is then filled.

–  Check the coolant level and top up coolant as far as the max mark. –  Start engine, run for 2 minutes (maximum) at approx. 1500 rpm and top up coolant to overflow hole on expansion tank with engine running. –  Close filler cap on coolant expansion tank. –  Run engine until radiator fan cuts in.   WARNING Hot steam/hot coolant can escape - risk of scalding. t  The cooling system is under pressure when the engine is hot. t  Cover filler cap on coolant expansion tank with a cloth and open carefully to dissipate pressure. –  Check coolant level and top up if necessary. l  When the engine is at normal operating temperature, coolant level must be at MAX mark, when engine is cold it must be between MIN and MAX marks. –  Switch engine off.