Oil Pump: Inspection

1. TIP CLEARANCE 

   Measure the tip clearance of rotors. If the clearance is out of standard, replace the rotors as a set.

   Tip clearance between inner and outer rotors:

   Standard

   0.04 - 0.14 mm (0.0016 - 0.0055 in)

   Courtesy of SUBARU OF AMERICA, INC.

2. CASE CLEARANCE 

   Measure the clearance between outer rotor and oil pump case. If clearance exceeds the standard, replace the oil pump case.

   Case clearance between outer rotor and pump case:

   Standard

   0.10 - 0.175 mm (0.0039 - 0.0069 in)

   Courtesy of SUBARU OF AMERICA, INC.

3. SIDE CLEARANCE 

   Measure the gap between the inner rotor and the oil pump case to measure the clearance between the inner rotor and the oil pump cover as shown in the figure. If clearance is out of standard, replace the rotor or the oil pump case.

   Side clearance between inner rotor and pump case:

   Standard

   0.02 - 0.07 mm (0.0008 - 0.0028 in)

   Courtesy of SUBARU OF AMERICA, INC.

4. OIL RELIEF VALVE 

   Check the valve for assembly condition and damage, and the relief valve spring for damage and deterioration.

   Replace the parts if defective.

   Relief valve spring:

   Free length

   73.7 mm (2.902 in)

   Installed length

   54.7 mm (2.154 in)

   Load when installed

   93.1 N (9.49 kgf, 20.93 lbf)

5. OIL PUMP CASE 

   Check for worn shaft hole, clogged oil passage, worn rotor chamber, cracks and other faults.

6. FRONT OIL SEAL 

Check the front oil seal lips for deformation, hardening, wear, etc. and replace if defective.