Oil Pump: Service and Repair

Fig, 17 Oil Pump Assembly 4.9L:

OIL PUMP
1. Raise car.
2. Remove oil pan.
3. Remove two screws and one nut securing oil pump to engine and remove pump. Discard O-ring.

OIL PUMP SERVICE
1. Remove five screws holding oil pump cover to housing. Fig. 17
2. Remove two screws each holding inlet and outlet pipes to housing, 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 nicks, burrs, chips or debris that may cause a leak or binding condition in rotor pocket of pump housing.
5. Inspect drive and driven rotors for nicks and burrs.
6. Check pump cover interior surface for excessive wear or score marks. Check for flatness.
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 at ends or evidence of twisting.
10. Ensure pressure relief valve closes by filling housing valve cavity with suitable light oil, no 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 no binding or roughness.
13. Install pump cover to housing and secure with five screws. Tighten to 10 Nm (8 lbs ft).
14. Using a new O-ring, install outlet pipe to housing. Tighten to 12 Nm (10 lbs ft).
15. Install inlet pipe to housing. Tighten to 12 Nm (10 lbs ft).
16. Temporarily install drive shaft into pump and rotate gears to make sure they turn freely without binding or roughness.
17. Position oil pump assembly and drive shaft to block engaging drive shaft to distributor gear. Use a new O-ring at the pump's outlet pipe. Secure to block with two screws and one nut. Tighten nut to 30 Nm (22 lbs ft) and screws to 20 Nm (15 lbs ft).
18. Install oil pan.
19. Lower car.