Cooling System, Checking For Leaks: Procedure

WARNING: This page is about a different car, the 2016 Audi A8 Quattro and 2015 Audi A8 Quattro. However, it is still accessible from the selected car via links, so may be relevant.

Engine at operating temperature.

WARNING:

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.

-- Open the coolant reservoir cap -arrow-.

Fig 1: Engine At Operating Temperature

Courtesy of AUDI OF AMERICA, LLC

-- Position the Cooling System Tester: VAG1274B with the Cooling System Tester - Adapter : VAG1274/8 on the coolant expansion tank.

Fig 2: Cooling System Tester VAG 1274B

Courtesy of AUDI OF AMERICA, LLC

-- Generate approximately 1.5 bar (21.75 psi) pressure using the cooling system tester hand pump.

The pressure must not drop more than 0.2 bar (2.9 psi) within 10 minutes.

-- If the pressure falls more than 0.2 bar (2.9 psi), search for leaks and correct the problem.

NOTE:

The pressure decrease of 0.2 bar (2.9 psi) within 10 minutes is a condition of the cooling of the coolant. The colder the engine the more the pressure decrease. If necessary repeat the test with the engine cold.