Checking the Pressure Relief Valve in the Version 1 Cap

Fig 1: Coolant Expansion Tank

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-- Position the :VAG1274B  with the :VAG1274B/15  on the cap.

Fig 2: Identifying VAG1274B & VAG1274B/15

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-- Generate approximately 2 bar (29 psi) pressure using the cooling system tester hand pump.

Blue Cap:

• The pressure must lower to 1.6 to 1.4 bar (23.20 to 20.30 psi) and stay there.

-- If the pressure relief valve does not react as specified, replace the cap.

Black Cap:

• The pressure must lower to 1.8 to 1.6 bar (26.1 to 23.2 psi) and stay there.

-- If the pressure relief valve does not react as specified, replace the cap.

Checking the Pressure Relief Valve in the Version 2 Cap:

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-- Position the :VAG1274B  with the :VAG1274/9  on the cap.

Fig 3: Identifying VAG1274B & VAG1274/9

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-- Generate pressure with the cooling system tester hand pump.

Blue Cap:

• The pressure relief valve must open at 1.4 to 1.6 bar (20.30 to 23.20 psi).

-- If the pressure relief valve does not react as specified, replace the cap.

Black Cap:

• The pressure relief valve must open at 1.6 to 1.8 bar (23.2 to 26.1 psi).

-- If the pressure relief valve does not react as specified, replace the cap.

Additional procedures depending on the model: Refer to COOLING SYSTEM, CHECKING FOR LEAKS .