Part number 4H0965567 is an original equipment manufacturer (OE) part number for auxiliary water pumps (also known as electric coolant pumps) used in multiple brands under the Volkswagen Group (VAG), including Audi, Porsche and Volkswagen.

Although the car water pump has a simple structure, it is the power source for the engine cooling system and is crucial to the engine’s health. Understanding its function, working principle, and common faults helps car owners to identify potential problems in a timely manner and perform proper maintenance, thus avoiding major issues and protecting the expensive engine.