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	Hose clip pliers -V.A.G 1921-

t	Cooling system charge unit -VAS 6096-

t	Drip tray for workshop hoist -VAS 6208-

t	Refractometer -T10007-

Draining   Note Collect drained coolant in a clean container for re-use or disposal.   WARNING Hot steam/hot coolant may escape when opening expansion tank; cover filler cap with cloth and open carefully. –  Open filler cap on coolant expansion tank.

–  Release quick-fasteners -1-, unscrew bolts -2- and take off noise insulation. –  Place drip tray for workshop hoist -VAS 6208- under engine.

–  Unscrew drain plug -arrow- at thermostat housing and drain off coolant at engine. Filling   Note t  The cooling system is filled all year round with a mixture of water and radiator antifreeze/anti-corrosion agent. t  It is important to use only coolant additive Plus -G 012 A8F A1- (also designated as “G12+”) “meeting specification TL VW 774 F”. 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  “G12+” and coolant additives marked “Meets specification TL VW 774 F” prevent frost and corrosion damage and stop scale from forming. 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 antifreeze concentration must be at least 40 %. t  If greater frost protection is required in very cold climates, the amount of “G 12+” can be increased, but only up to 60% (this gives frost protection to about –40 °C). If the antifreeze 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  To check frost protection level of coolant additive “G12+” you must use a refractometer -T10007-.

–  Install drain plug -arrow- with new seal.

–  Fill reservoir of cooling system charge unit -VAS 6096- with at least 12 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 -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 both valves -A- and -B- (turn lever perpendicular 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 for cooling system charge unit -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. l  The needle on the gauge should remain in the green zone. –  Close valve -B-. l  The needle on the gauge must 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 vacuum in the cooling system causes the coolant to be drawn out of the reservoir for 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 expansion tank.

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

–  Pull off rubber seal on plenum chamber cover. –  Remove plenum chamber cover -1- to front -arrows-.

–  Push back protective cover for coolant hoses on connection for heat exchanger. –  Release coolant hose going to heat exchanger and pull back hose until bleeder hole in hose -arrow- is no longer blocked by the connection. –  Top up the coolant until it emerges from the bleed hole in the coolant hose without bubbles. –  Push coolant hose onto connection and tighten. –  Tighten filler cap on expansion tank. –  Start engine. –  Set heater/air conditioner to “HI”. –  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 can be above the MAX marking when the engine is warm. Tightening torque

Component	Nm
Drain plug in thermostat housing	25