Cooling System, Checking For Leaks

WARNING: This page is about a different car, the 2020 Audi A3, 2019 Audi A3, and 2018 Audi A3. However, it is still accessible from the selected car via links, so may be relevant.

Special tools and workshop equipment required

Cooling System Tester: VAG1274B
Cooling System Tester - Adapter: VAG1274/8
Adapter: VAG1274B/15
Cooling System Tester - Adapter: VAG1274/9

Procedure

Engine at operating temperature.
Ignition switched off.

CAUTION:

The Cooling System Is Under Pressure When the Engine Is Warm. 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.

-- Remove the coolant expansion tank cap -arrow-.

Fig 1: Identifying Coolant Reservoir Cap

Courtesy of AUDI OF AMERICA, LLC

-- Position the : VAG1274B with the : VAG1274/8 on the coolant expansion tank.

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-- 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.

Cap, Version 1:

Fig 2: Coolant Expansion Tank

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

Courtesy of AUDI OF AMERICA, LLC

-- 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.

Cap, Version 2:

Courtesy of AUDI OF AMERICA, LLC

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

Courtesy of AUDI OF AMERICA, LLC

-- 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.