During the operation of the piston air compressor, if the exhaust gas contains engine oil, it may be caused by the following reasons:

1.Piston ring wear: Severe wear of the piston ring can cause the lubricating oil in the crankcase to leak, which can then be mixed into the compressed air and discharged with the gas.

2.Excessive lubricating oil: Adding too much lubricating oil to an air compressor may increase the oil pressure, causing the oil to leak into the compressed air.

3.Cylinder channeling: Wear of the piston oil ring can lead to a decrease in sealing performance, allowing the oil in the cylinder to enter the compressed air passage.

4.Poor sealing of suction valves: Dust or carbon deposits on the edges of suction valves can lead to poor sealing, causing oil leakage.

5.Air filter problems: If the air filter is too dirty or lacks filter material, it can lead to incomplete separation of oil and gas, allowing the oil to be discharged with the air.

6.Clogged return lines: Blockages of foreign objects in the return lines or check valves and return filters can prevent the separated oil from flowing back to the head, causing the oil to be carried away by the airflow.

7.Oil return check valve damage: If the oil return check valve is damaged, it may cause the oil to be poured back into the oil after the shutdown of the oil tank, and part of the oil is discharged with the air.

For these reasons, corresponding inspection and maintenance measures should be taken to ensure the normal operation of the air compressor and compress the air quality.