Cooling System, Checking For Leaks

WARNING: This page is about a different car, the 2024 Audi Q3 and 2023 Audi Q3. However, it is still accessible from the selected car via links, so may be relevant.

Special tools and workshop equipment required

Cooling System Tester:V.A.G 1274B

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

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

Fig 3: Cooling System Tester - Adapter VAG1274/9
Courtesy of AUDI
Adapter:V.A.G 1274B/15

Fig 4: Adapter VAG1274B/15
Courtesy of AUDI

Procedure

Engine at operating temperature.
Ignition switched off.

CAUTION:

The cooling system may be under pressure. 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 suitable towel and carefully opening it.

-- Open the coolant expansion tank cap.

-- 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

Courtesy of AUDI

-- Generate approximately 1 bar (14.5 psi) pressure using the cooling system tester hand pump.

-- If the pressure falls, search for leaks and correct the malfunction.

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.

Pressure Relief Valve in Cap, Checking

Cap, Version 1:

Fig 6: Coolant Expansion Tank

Courtesy of AUDI

-- Position the Cooling System Tester:V.A.G 1274B with the Adapter:V.A.G 1274B/15 on the cap.

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

Fig 7: Identifying VAG1274B & VAG1274B/15

Courtesy of AUDI

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.

Cap, Version 2:

Courtesy of AUDI

-- Position the Cooling System Tester:V.A.G 1274B with the Cooling System Tester - Adapter:V.A.G 1274/9 on the cap.

Fig 8: 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 pressure relief valve does not open 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 pressure relief valve does not open as specified, replace the cap.