Cooling System: Testing and Inspection

Cooling System, Checking for Leaks

=> [ Pressure Relief Valve in Cap, Checking ]

Special tools, testers and auxiliary items required

• Cooling System Tester (V.A.G 1274)

• Adapter (V.A.G 1274/8)

• Adapter (V.A.G 1274/9)

Pressure relief valve in cap, checking. Refer to => [ Pressure Relief Valve in Cap, Checking ].

• Engine is at operating temperature.

Test Sequence:


Hot steam may escape when opening the expansion tank cap. Wear protective goggles and protective clothing to prevent damage to eyes and scalding. Cover the cap with a cloth and open very carefully.

- Open the cap on the coolant expansion tank.

- Install the cooling system tester (V.A.G 1274) with the adapter (V.A.G 1274/8) onto the expansion tank.






- Generate a positive pressure of approximately 1.0 bar using the hand pump on the tester.

If the pressure drops:

- Search for leaking areas and repair the malfunction.

Pressure Relief Valve in Cap, Checking






- Install the cap to the adapter (V.A.G 1274/9) and the cooling system tester (V.A.G 1274).

- Operate the hand pump.

• The relief valve must open at 1.4 to 1.6 bar.