Checking the pressure relief valve in the coolant expansion tank cap
WARNING: This page is about a different car, the 2022 Audi S3, 2022 Audi RS 3, 2022 Audi A3 Quattro, and 2022 Audi A3. However, it is still accessible from the selected car via links, so may be relevant.
-- Position the Cooling System Tester: V. A. G 1274B with the Cooling System Tester - Adapter : V. A. G 1274/9 on the cap (example illustration).
-- Generate pressure with the cooling system tester hand pump.
- 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.