Oil pump is one of the main components of engine lubrication system. It can absorb the oil of engine oil pan, then generate pressure through the internal and external rotors of the oil pump, and finally transport the oil to all moving parts of the engine through the engine lubrication oil duct for lubrication. If the oil pump fails, it will lead to poor engine lubrication, engine abnormal noise, piston cylinder pulling and other faults. The oil pump works under high load, and it is also one of the parts that often break down in the engine. So it is very important to understand the maintenance of the oil pump. The following is a detailed description of the maintenance methods of the oil pump:
(1) Remove the bolts on the oil pump housing, and then separate the oil pump housing from the oil pump cover.
(2) Check the radial clearance between the inner rotor and the outer rotor of the oil pump. If the radial clearance between the inner rotor and the outer rotor exceeds the maintenance limit (for example, Honda car is 0.20 mm), replace the oil pump.

(3) Check the axial clearance between the oil pump shell and the rotor. If the axial clearance between the oil pump housing and the rotor exceeds the maintenance limit (e.g. Honda car is 0.12 mm), replace the oil pump.

(4) Check the radial clearance between the oil pump shell and the external rotor. If the radial clearance between the oil pump housing and the outer rotor exceeds the maintenance limit (e.g. Honda car is 0.20 mm), replace the oil pump.

(5) Check whether there are scratches or other damages in the two internal and external rotors and oil pump housing. If damaged, the damaged parts must be replaced.
(6) Install the oil pump cover, and then check whether the oil pump can rotate freely. If it is normal, install the oil pump drive belt.