Checking the Pressure Relief Valve in the Version 1 Cap

Fig 1: Coolant Expansion Tank

Courtesy of AUDI

-- Position the Cooling System Tester:VAG1274B  with the Adapter:VAG1274B/15  on the cap.

Fig 2: Identifying VAG1274B & VAG1274B/15

Courtesy of AUDI

-- Generate approximately 2 bar (29.01 psi) pressure using the cooling system tester hand pump.

Blue Cap:

• The pressure must lower to 1.6 to 1.4 bar (23.21 to 20.31 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 (26.11 to 23.21 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:

Courtesy of AUDI

-- Position the Cooling System Tester:VAG1274B  with the Cooling System Tester - Adapter:VAG1274/9  on the cap.

Fig 3: Identifying VAG1274B & VAG1274/9

Courtesy of AUDI

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

Blue Cap:

• The pressure release valve must open at 1.4 to 1.6 bar (20.31 to 23.21 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 (23.21 to 26.11 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 .