Oil Pump: Testing and Inspection

1. Inspect relief valve.
Coat the valve with engine oil and check that it falls smoothly into the valve hole by its own weight.
If it does not, replace the relief valve. If necessary, replace the oil pump assembly.





2. Place the drive and driven rotors into the oil pump body with the mark facing upward.





3. Inspect rotor side clearance. Using a feeler gauge and precision straight edge, measure the clearance between the rotors and precision straight edge.
Standard side clearance: 0.030 - 0.090 mm (0.0012 - 0.0035 inch)
Maximum side clearance: 0.15 mm (0.0059 inch)
If the side clearance is greater than maximum, replace the rotors as a set. If necessary, replace the oil pump assembly.





4. Inspect rotor tip clearance. Using a feeler gauge, measure the clearance between the drive and driven rotor tips.
Standard tip clearance: 0.110 - 0.240 mm (0.0043 - 0.0094 inch)
Maximum tip clearance: 0.35 mm (0.0138 inch)
If the tip clearance is greater than maximum, replace the rotors as a set.





5. Inspect rotor body clearance. Using a feeler gauge, measure the clearance between the driven rotor and body.
Standard body clearance: 0.100 - 0.175 mm (0.0039 - 0.0069 inch)
Maximum body clearance: 0.30 mm (0.0118 inch)
If the body clearance is greater than maximum, replace the rotors as a set. If necessary, replace the oil pump assembly.