A versatile compact air precleaner, air cleaning method and disposable air filter cartridge for air precleaner for separating heavier-than-air particulate debris from debris laden air to provide a clean airflow, wherein a flow path for air passing through a separator chamber of the air precleaner is retroflexed en route to the outlet. A plurality of independently rotatably adjustable housing sections of a housing provide utility with multiple clean air outlet configurations, freedom of direction of ejection of particulate debris from the ejector ports, different inlet configurations, mounting of the precleaner from different sides, accommodation of different sizes of filters, and different clean airflow rate capabilities. A separator chamber end section including the ejector ports is connected to the filter as a removable, disposable air filter cartridge to obviate ejector port clogging with change of filters.