Oil Pump: Service and Repair

Fig, 17 Oil Pump Assembly 4.9L:

1. Remove oil pump cover to housing attaching screws, Fig. 17.
2. Remove inlet and outlet pipes attaching screws, then remove and discard O-rings.
3. Slide inner and outer rotors from housing. Pressure relief valve is not removable.
4. Inspect pump housing for damage that may cause a leak or binding condition in rotor pocket.
5. Inspect drive and driven rotors for nicks and burrs.
6. Inspect interior pump surface for excessive wear or scoring.
7. Inspect pump housing cover, inlet and outlet pipes for flatness.
8. Inspect inlet screen and pipe for debris.
9. Inspect pump driveshaft for wear or twisting.
10. Ensure pressure relief valve closes by filling housing valve cavity with suitable light oil, not oil leakage should be indicated.
11. Install outer rotor in rotor pocket with slots toward bottom of pump.
12. Slide inner rotor inside driven rotor with internal hex towards top of pump, then rotate gears ensuring not binding or roughness.
13. Install pump cover, tighten to specifications.
14. Install inlet pipe to housing, tighten to specifications.
15. Temporarily install driveshaft to pump, then rotate gears ensuring no binding or roughness.