Cooling System: Testing and Inspection

Cooling System, Checking for Leaks

Special tools, testers and auxiliary items required

• Cooling System Tester (V.A.G 1274 B)

• Adapter (V.A.G 1274/8)

• Adapter (V.A.G 1274/9)

Test Conditions

• The 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 coolant expansion tank cap.

- Install the adapter (V.A.G 1274/8) onto the coolant expansion tank.

- Clamp the connecting piece (V.A.G 1274 B/1) on the adapter (V.A.G 1274/8).

- Connect the connector piece (V.A.G 1274 B/1) to the cooling system tester (V.A.G 1274 B) using the connecting hose.






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

Risk of scalding! Reduce the pressure before disconnecting the cooling system tester (V.A.G 1274 B) from the connecting hose or connector piece (V.A.G 1274 B/1). To do this, press the pressure release valve on the cooling system tester (V.A.G 1274 B) until the pressure gauge displays 0.

If the pressure drops:

- Search for the leaking areas and repair the malfunction.

Checking the Pressure Relief Valve inside the Cap

- Install the cap to the adapter (V.A.G 1274/9).

- Clamp the connecting piece (V.A.G 1274 B/1) on the adapter (V.A.G 1274/9).

- Connect the connector piece (V.A.G 1274 B/1) to the cooling system tester (V.A.G 1274 B) using the connecting hose.






- Actuate the hand pump.

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

If the pressure relief valve opens too early or too late:

- Replace the cap.