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

Clearance

Standard (New): 0.040-0.085 mm (0.002-0.003 in)

Service Limit: 0.20 mm (0.007 in)

Fig 1: Checking Inner Rotor-To-Outer Rotor Radial Clearance
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.
Pump Housing-to-rotor Axial Clearance

Standard (New): 0.020-0.065 mm (0.001-0.002 in)

Service Limit: 0.12 mm (0.004 in)

Fig 2: Checking Pump Housing-To-Rotor Axial Clearance
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): 0.100-0.140 mm (0.004-0.005 in)

Service Limit: 0.20 mm (0.007 in)

Fig 3: Checking Pump Housing-To-Outer Rotor Radial Clearance
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Inspect both rotors and the pump housing for scoring or other damage. Replace the oil pump assembly, if necessary.
Apply liquid thread lock to the pump housing screws, then install the oil pump cover.
Check that the oil pump turns freely.