Oil Pump Overhaul: Inspection

NOTE: Refer to the EXPLODED VIEW if needed during this procedure.

Remove the screws from the pump housing, then separate the housing and the cover.
Check the inner-to-outer rotor radial clearance between the inner rotor (A) and the outer rotor (B). If the inner-to-outer rotor radial clearance exceeds the service limit, replace the oil pump assembly.
Inner Rotor-to-Outer Rotor Radial Clearance

Standard (New): 0.06-0.16 mm (0.0024-0.0063 in)

Service Limit: 0.20 mm (0.0079 in)

Fig 1: Checking Inner-To-Outer Rotor Radial Clearance Between Inner Rotor And Outer Rotor
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Check the pump housing-to-rotor axial clearance between the rotors (A) and the pump housing (B). If the pump housing-to-rotor axial clearance exceeds the service limit, replace the oil pump assembly.
Housing-to-Rotor Axial Clearance

Standard (New): 0.02-0.06 mm (0.0008-0.0024 in)

Service Limit: 0.15 mm (0.0059 in)

Fig 2: Checking Pump Housing-To-Rotor Axial Clearance Between Rotors And Pump Housing
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Check the pump housing-to-outer rotor radial clearance between the outer rotor (A) and the pump housing (B). If the pump housing-to-outer rotor radial clearance exceeds the service limit, replace the oil pump assembly.
Pump Housing-to-Outer Rotor Radial Clearance

Standard (New): 0.100-0.175 mm (0.00394-0.00689 in)

Service Limit: 0.20 mm (0.0079 in)

Fig 3: Checking Pump Housing-To-Outer Rotor Radial Clearance Between Outer Rotor And Pump Housing
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Inspect both rotors and the pump housing for scoring or other damage. Replace parts, if necessary.
Check that the oil pump turns freely.