Component Tests and General Diagnostics

Cooling System, Checking for Leaks

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)

Test Conditions

• Engine at operating temperature.

Test Sequence


Cover the cap of the expansion tank with a rag and open carefully, as hot steam for example hot coolant may escape when opening.

- Open the cap of coolant expansion tank.

- Attach (V.A.G 1274) with (V.A.G 1274/8) to the expansion tank.






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

- If the pressure decreases, search for leaking areas and repair the malfunction.

Pressure Relief Valve in Cap, Checking

- Attach (V.A.G 1274) with (V.A.G 1274/9) to sealing cap.






- Operate hand pump.

• The pressure release valve must open at 1.4 to 1.6 bar.