The oil pump appears similar to those used in gasoline engines, but this one is a disposable item.

To determine the quality of a plunger-type oil pump's sealing performance, the experience method is to suck through the oil intake with your mouth. If you can suck the tip of your tongue, it indicates good sealing of the intake valve. Blocking the intake, if you can still suck the tip of your tongue, it means the oil cup gasket, pump body, and pump cover are well-sealed. Blowing out through the oil outlet, if it's not blown out, it indicates good sealing of the outlet valve.

To determine the quality of an oil pump, connect an oil pipe to the intake of the oil pump and insert the other end of the pipe into diesel or water. Swing the lever, and if the oil ejected from the outlet is strong and rapid, the pump oil effect is good.