a filter system in which a housing and an environmentally friendly filter cartridge are coordinated to provide ease of change of the filter cartridge and reliable operation . the cartridge contains no metal parts and is readily incinerateable . the housing is provided with a number of “ universality ” features including a changeable bottom which allows the housing to operate as a fuel filter , a lubrication filter , or a hydraulic filter in different applications . the housing and cartridge are configured to provide support for the plastic elements of the cartridge to prevent crushing of the filter under normal and abnormal filter operating conditions . a key system associated with the cartridge and the housing provides assurance that the correct filter is installed for a particular application .