Audi Workshop Service and Repair Manuals

Checking cooling system for leaks Special tools and workshop equipment required

t  Cooling system tester -V.A.G 1274 B-

t  Adapter for cooling system tester -V.A.G 1274/8- (for vehicles with large filler cap) or -V.A.G 1274/1- (for vehicles with small filler cap)

t  Adapter for cooling system tester -V.A.G 1274/9- Procedure

l  Engine must be warm.   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.

–  Fit cooling system tester -V.A.G 1274 B- with adapter -V.A.G 1274/8- (for vehicles with large filler cap) or -V.A.G 1274/1- (for vehicles with small filler cap) onto coolant expansion tank. –  Using hand pump on cooling system tester, build up a pressure of approx. 1.0 bar. –  If this pressure is not maintained, locate and rectify leaks.

Checking pressure relief valve in filler cap –  Fit cooling system tester -V.A.G 1274 B- with adapter -V.A.G 1274/9- onto filler cap. –  Build up pressure with hand pump on cooling system tester. l  The pressure relief valve should open at a pressure of 1.4 ... 1.6 bar. –  Renew filler cap if pressure relief valve does not open as described.