What is air mixed

Air into a state , in this state, separation bubbles are caught when the pump fluid into the liquid flow . Usually observed with the naked eye can identify the cause. Coerced bubbles may be in the air from a height into the oil return generated when the mailbox , it may be in  Hydraulic pipe fittings effect through inhalation of a large group of vortex air generated in the tank when the oil level is too low it will happen whirlpool effect .Sometimes one has quality problems or incorrectly installed seals, or incorrectly assembled fittings will put air into the suction side piping ( oil does not leak ) . When you suspect suction side of the leak , the high viscosity of the oil flooded with these points , the noise emitted by making significant changes in the pump can usually find a leak site . A suction pump issue seems empty aqueous gargling sounds.