Disclosed is a liquid filter for an internal combustion engine. The filter has a housing, a removable cover for closing the housing, and a replaceable filter insert that has a filter surface through which liquid can flow. The filter surface defines a boundary between a flow channel on the filtered side and a flow channel on the unfiltered side of the filter. A non-return valve allows the liquid to flow through the filter at pressure conditions that prevail when the engine is running. When the engine is shut off, the non-return valve prevents flow of liquid through the filter, thereby holding within the filter housing the liquid that was in the filter when the engine was shut off. The non-return valve is placed in the flow channel on the filtered side.