A pressure regulator is a valve that controls air flow from a compressor. This valve dictates the amount of pressure or pounds per square inch (PSI) of air. Noises from the regulator indicate an air leak or obstruction.
Turn off the power to the air compressor. Pull the pressure release valve to release the air pressure. The valve is a small metal and plastic valve near the outlet valve on the compressor.
Find the nut for the fitting at the bottom of the pressure regulator. Turn the nut counter-clockwise with the wrench. Continue turning the nut until you can remove it by hand.
Disconnect the pressure regulator from the air compressor. Examine the threads on the connection and see if any Teflon tape is present. Wrap Teflon tape around the threads if there is none present.
Insert the pressure regulator back into the air compressor. Tighten the nut for the fitting with the wrench.
Turn the air compressor on and allow it to build pressure in the tank. Check to see if the noise from the pressure regulator is gone by using the air compressor as you normally would.
Remove the adjustment knob at the top of the pressure regulator by loosening the nut under the knob with the wrench. Remove the knob and top section of the pressure regulator.
Lubricate the rubber washer on the regulator assembly with the air tool oil. Reattach the top section of the pressure regulator and the adjustment knob.
Replace the pressure regulator with a new part if the noise does not go away.