Oil Pump: Service and Repair
OIL PUMPREMOVAL
It is necessary to remove the oil pump body to service the oil pump rotors.
The oil pump pressure relief valve can be serviced by removing the oil pan.
1. Drain the cooling system.
2. Remove the radiator fan.
3. Remove the accessory drive belts.
4. Remove the timing belt.
5. Remove the crankshaft sprocket.
6. Remove the oil pan.
7. Remove the oil pickup tube.
8. Remove the oil pump fasteners. Remove pump and gasket from engine (Fig. 109).
DISASSEMBLY
1. To remove the relief valve, proceed as follows:
2. Remove cotter pin. Drill a 3.175 mm (1/8 in.) hole into the relief valve retainer cap and insert a self-threading sheet metal screw into cap.
3. Clamp screw into a vise and while supporting oil pump body, remove cap by tapping oil pump body using a soft hammer. Discard retainer cap and remove spring and relief valve (Fig. 110).
4. Remove oil pump cover screws, and lift off cover.
5. Remove pump rotors.
6. Wash all parts in a suitable solvent and inspect carefully for damage or wear (Fig. 111).
CLEANING
1. Clean all parts thoroughly in a suitable solvent.
INSPECTION
1. Disassemble oil pump.
2. Clean all parts thoroughly. Mating surface of the oil pump housing should be smooth. Replace pump cover if scratched or grooved.
3. Lay a straightedge across the pump cover surface (Fig. 112). If a 0.025 mm (0.001 in.) feeler gauge can be inserted between cover and straight edge, cover should be replaced.
4. Measure thickness and diameter of outer rotor. If outer rotor thickness measures 14.299 mm (0.563 in.) or less (Fig. 113), or if the diameter is 79.78 mm (3.141 inches.) or less, replace outer rotor.
5. If inner rotor measures 14.299 mm (0.563 in.) or less replace inner rotor (Fig. 114).
6. Slide outer rotor into body, press to one side with fingers and measure clearance between rotor and body (Fig. 115). If measurement is 0.39 mm (0.015 in.) or more, replace body only if outer rotor is in specifications.
7. Install inner rotor into body. If clearance between inner and outer rotors (Fig. 116) is 0.20 mm (0.008 in.) or more, replace both rotors.
8. Place a straightedge across the face of the body, between bolt holes. If a feeler gauge of 0.077 mm (0.003 in.) or more can be inserted between rotors and the straightedge, replace pump assembly (Fig. 117) ONLY if rotors are in specs.
9. Inspect oil pressure relief valve plunger for scoring and free operation in its bore. Small marks may be removed with 400-grit wet or dry sandpaper.
10. The relief valve spring (Fig. 118) has a free length of approximately 49.5 mm (1.95 in.) it should test between 101 - 110 N (23 - 25 lbs.) when compressed to 34 mm (1-11/32 in.). Replace spring that fails to meet specifications.
11. Assemble oil pump.
ASSEMBLY
1. Assemble oil pump using new parts as required.
2. Tighten cover screws to 12 Nm (105 in. lbs.) (Fig. 111).
3. Prime oil pump before installation by filling rotor cavity with engine oil.
4. If oil pressure is low and pump is within specifications, inspect for worn engine bearings or other reasons for oil pressure loss.
INSTALLATION
1. Prime oil pump before installation by filling rotor cavity with engine oil.
2. Install oil pump and gasket carefully over the crankshaft. Position pump onto block and tighten bolts to 28 Nm (250 in. lbs.)
3. Install new O-ring on oil pickup tube.
4. Install oil pickup tube.
5. Install oil pan.
6. Install crankshaft sprocket.
7. Install timing belt.
8. Install the timing belt covers.
9. Install the crankshaft vibration damper.
10. Install the accessory drive belts.
11. Install the radiator fan.
12. Fill the cooling system.
13. Fill engine crankcase with proper oil to the correct level.