Oil Pump Overhaul: Inspection

NOTE: Refer to the Exploded View Exploded View as needed during this procedure.

Remove the screws from the pump housing, then separate the pump housing and the pump 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 clearance exceeds the service limit, replace the oil pump assembly.
Inner Rotor-to-Outer Rotor Radial

Clearance

Standard (New): 0.04-0.16 mm (0.0016 -0.0063 in)

Service Limit: 0.20 mm (0.0079 in)

Fig 1: Checking Clearance Between Inner Rotor & 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.
Pump housing-to-Rotor Axial

Clearance

Standard (New): 0.02-0.07 mm (0.008 -0.0028 in)

Service Limit: 0.12 mm (0.0047 in)

Fig 2: Checking Pump Housing-To-Rotor Axial Clearance Between Rotors & 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): 0.10-0.19 mm (0.0039 -0.0075 in)

Service Limit: 0.20 mm (0.0079 in)

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