3/8" Breather/Oil Fill Plug

This is a genuine OEM replacement part sourced directly from Rolair. This part serves two main functions, it is a plug to ensure oil is not escaping the crankcase as the crankshaft rotates and the pistons pump, it also acts as a vent. As the crankcase ventilation system gets older the pistons will not be as effective and the crankcase will retain some of the pressure created, this breather releases the pressure from the crankcase to avoid a buildup. Overtime this part can build up with sediment and debris, it is important to routinely check it, and ensure it is operating properly. Before you start any repairs on an air compressor unplug the machine, and make sure to drain the air out of the compressor tank.