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

• Engine at operating temperature.

Perform the following:


Risk of scalding due to hot steam and hot coolant.

• The coolant system is under pressure when the engine is warm.

• Wear protective goggles and protective clothing to prevent damage to eyes and scalding.

• Reduce pressure by covering coolant reservoir cap with a cloth and carefully opening.

- Open the reservoir.

- Install the adapter for cooling system tester V.A.G 1274/8 (V.A.G 1274/8) into the coolant reservoir.






- Clamp the connection (V.A.G 1274 B/1) on the adapter for cooling system tester V.A.G 1274/8 (V.A.G 1274/8).

- Connect the connection (V.A.G 1274 B/1) to the coolant system tester (V.A.G 1274 B) using the hose provided.

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


Risk of scalding!

• Any pressure still present must be relieved before disconnecting the cooling system tester (V.A.G 1274 B) from the connecting hose or from the connecting piece (V.A.G 1274 B).

• 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 leaking areas and repair the malfunction.

Pressure Relief Valve in Cap, Checking

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






- Clamp the connection (V.A.G 1274 B/1) on the adapter for cooling system tester V.A.G 1274/8 (V.A.G 1274/9).

- Connect the connection (V.A.G 1274 B/1) to the coolant system tester (V.A.G 1274 B) using the hose provided.

- Actuate the hand pump.

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

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

- Replace the cover.