Service of Audi A4 from 2001 to 2005 release.
	1. Operation and maintenance of the car
	2. Engine
		2.1. General information
		2.2. Predvaritlny checks
		2.3. Mekhanichsky part (petrol engines 2,0l)
		2.4. Lubrication system
		2.5. Cooling system
			2.5.1. Removal and installation of the thermostat of the cooling system operated on an algorithm
			2.5.2. Check of the thermostat of the cooling system operated on an algorithm
			2.5.3. Removal and installation of the water pump
			2.5.4. Pressure testing of the cooling system
		2.6. System of injection
		2.7. System of production of the fulfilled gases
		2.8. Mechanical part (petrol engines 3,0; 3,2 l)
		2.9. Mechanical part (petrol engines of 4,2 l)
		2.10. Mechanical part (diesel engines of 2,0 l)
		2.11. Tables
	3. Transmission
	4. Running gear
	5. Steering mechanism
	6. Brake system
	7. Onboard electric equipment
	8. Body
	9. Schemes of electric equipment

2-5-4-opressovka-sistemy-okhlazhdeniya.html

2.5.4. Pressure testing of the cooling system

The engine has to have working temperature.

Procedure for test

Open a cover of a broad tank of the cooling system.

Fig. 2.215. Installation of a tester with an adepter on a broad tank

Establish a cooling system tester with the adapter on a broad tank (fig. 2.215).

By means of the manual pump of a tester create pressure about 1,0 bars.

If pressure constantly falls, to find and eliminate leakage.

Check of the reducing valve in a cover

Fig. 2.216. Installation of a tester with an adepter on a tank cover

Establish a cooling system tester with the adapter on a cover of a tank (fig. 2.216).

Involve the manual pump.

With an excessive pressure of 1,4-1,6 bars the reducing valve has to open.