W250 3/4 Ton Pickup 4WD V8-318 5.2L VIN R 4-bbl (1982)
Air Injection Pump: Description and Operation
Fig.1 Air Injection Pump With Centrifugal Filter Fan
The air pump is mounted on the front of the engine and is belt driven off the crankshaft pulley. Intake air is passed through a centrifugal fan at the
front of the pump which separates foreign materials from the air by centrifugal force. Air is delivered to the air injection manifold and check valve
tube assembly by a rubber hose through the diverter valve and switching valve, if used.
The only serviceable component of the pump is the centrifugal fan filter, Fig. 1.