Cooling System, Checking For Leaks: Notes

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Special tools and workshop equipment required

Cooling System Tester: V. A. G 1274B

Fig 1: Cooling System Tester VAG1274B
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Cooling System Tester - Adapter: V. A. G 1274/8

Fig 2: Identifying Cooling System Tester Adapter
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Cooling System Tester - Adapter: V. A. G 1274/9

Fig 3: Cooling System Tester - Adapter VAG1274/9
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Procedure

To perform the leak test correctly, a check (self-test) of the Cooling System Tester : V. A. G 1274 B must be performed first.

Check (self-test) Cooling System Tester: V. A. G 1274B

Fig 4: Special Tool VAG1274B

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-- Operate the Cooling System Tester: V. A. G 1274 B multiple times.

-- Create a pressure of 3.0 bar (43.51 psi) on the cooling system tester.

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-- Pay attention to the pressure on the pressure gauge of the Cooling System Tester : V. A. G 1274 B for 30 seconds.

If pressure is not built up or if the pressure falls again:

The Cooling System Tester: V. A. G 1274 B is leaking and must not be used.

Cooling System, Checking for Leaks

Engine at operating temperature.
Ignition switched off.

CAUTION:

The cooling system is under pressure when the engine is warm. There is a risk of scalding due to hot steam and hot coolant.

Scalding the skin and other parts of the body is possible.

- Wear safety gloves.

- Wear protective eyewear.

- Reduce the pressure by covering the coolant expansion tank cap with a cloth and carefully opening it.

-- Open the coolant reservoir cap -arrow-.

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-- Position the Cooling System Tester: V. A. G 1274B with the Cooling System Tester - Adapter : V. A. G 1274/8 on the coolant expansion tank.

Fig 5: Identifying VAG1274B & VAG1274/8

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-- Generate approximately 1.5 bar (21.76 psi) pressure using the cooling system tester hand pump.

The pressure must not drop more than 0.2 bar (2.9 psi) within 10 minutes.
The pressure decrease of 0.2 bar (2.9 psi) within 10 minutes is a condition of the cooling of the coolant. The colder the engine the more the pressure decrease. If necessary repeat the test with the engine cold.

If the pressure falls more than 0.2 bar:

-- Check the engine and radiator for leaks and correct.

CAUTION:

There is a risk of scalding due to hot steam and hot coolant.

Scalding the skin and other parts of the body is possible.

- Reducing the pressure: press the pressure release valve on the cooling system tester until the pressure gauge displays a value of 0.