Checking the cooling system under pressure (Audi A3 8L)

The tightness of the system and the operation of the relief valve in the radiator cap can be checked using the 4800⁻¹ pump.

Execution order

1. Warm up the engine until the gauge shows normal operating coolant temperature.

Warning: When the engine is hot, place a thick cloth on the expansion tank before opening it to prevent hot liquid and vapors from escaping, which could cause a burn. The cap can only be opened when the liquid temperature is below +90°C.

2. Install a pressure tester, such as the HAZET 4800⁻¹ with adapter 4800, on the expansion tank connection^–5.

3. Create an excess pressure of about 1.0 bar using the hand pump of the device and maintain it. If the pressure drops, visually check the system for leaks and eliminate leaks.



4. To test the safety valve, install the HAZET 4800–1 device with the 4800–5 adapter on the expansion tank cap. Create excess pressure with the hand pump. At a pressure of 1.4–1.6 bar, the safety valve should operate.