Checking the Pressure Relief Valve in the Version 1 Cap

WARNING: This page is about a different car, the 2021 Audi S5 Sportback and 2020 Audi S5 Sportback. However, it is still accessible from the selected car via links, so may be relevant.

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 1.4 to 1.6 bar (20.30 to 23.20 psi) and stay there.

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

Black Cap:

The pressure must lower to 1.6 to 1.8 bar (23.2 to 26.1 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 release 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 release 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: COOLING SYSTEM, CHECKING FOR LEAKS .