Oil Pump: Service and Repair

Fig. 50 Oil pump cover & bypass valve. V6-231:

V6-231
Removal & Disassembly
1. Remove oil filter.
2. Disconnect wire from oil pressure indicator switch in filter bypass valve cap (if so equipped).
3. Remove screws attaching oil pump cover to timing chain cover. Remove cover and slide out pump gears. Replace any parts not serviceable.
4. Remove oil pressure relief valve cap, spring and valve, Fig. 50.
5. Check relief valve in its bore in cover. Valve should have no more clearance than an easy slip fit. If any perceptible side shake can be felt, the valve and/or cover should be replaced.
6. The filter bypass valve should be flat and free of nicks and scratches.

Fig. 51 Checking clearance between oil pump gear & housing gasket surface. V6-231:

Fig. 52 Checking oil pump side clearance. V6-231:

Fig. 53 Checking oil pump gear pocket for wear. V6-231:

Fig. 54 Checking oil pump gears for wear. V6-231:

Assembly & Installation
1. Lubricate and install pressure relief valve and spring in bore of pump cover. Install cap and gasket. Torque cap to 30---35 ft. lbs.
2. Install pump gears and shaft in pump body section of timing chain cover to check gear end clearance. Check clearance as shown in Fig. 51. If clearance is less than .0020 inch, check timing chain cover for evidence of wear.
3. Check oil pump side clearance as shown in Fig. 52. Clearance should be .002---.005 inch. If clearance is not as specified, measure gears and pocket to determine which is at fault, Figs. 53 and 54.
4. Check oil pump cover for wear with straightedge and feeler gauge. If clearance is greater than .001 inch, replace cover.
5. If clearances are as specified, remove gears and pack gear pocket with petroleum jelly.
6. Reinstall gears so petroleum jelly is forced into every cavity of gear pocket and between teeth of gears. Unless pump is packed with petroleum jelly, it may not prime itself when engine is started.
7. Install cover and tighten screws alternately and evenly. Final tightening is 10---15 ft. lbs. torque. Install filter on nipple.