Section XII. OIL PUMP AND OIL PAN ASSEMBLY14-64. General.The gear-type oil pump is mounted on thefront of the cylinder block and the drive gear mesheswith the crankshaft gear.b. A reIief valve, located in the oil pump out-let, bypasses oil back to the oil pan when the press-ure exceeds 82 to 98 psi. This relieves excessivedischarge pressure when starting a cold engine andcuts down wear on the oil pump gears.c.The oil pan serves as a bottom cover forthe crankshaft and a reservoir for the lubricatingoil. A finned steel tube is installed in the oil pan.Heated coolant is circulated through the tube to pre-heat the oil to aid in engine starting in sub-freezingtemperatures.14-65. Removal and Disassembly.a.Symptoms and Isolation of Malfunction. Amalfunction of the oil pump or a leak in the oil pumpis usually indicated by 10SS of oil pressure which re-sults in engine shutdown.To isolate the malfunction,proceed as follows(1) Examine the oil pan for evidence ofleakage. Leaking oil can be detected on top of thefuel tank located directly below the oil pan.(2) Check the oiI Ievel If the level iS suff-cient for normal operation, and engine has shut-downdue to loss of oil pressure, the malfunction is prob-ably the result of oil pump failure. Isolate oil pumpfailure as follows:(a) Remove valve cover. Refer to TM5-6115-545-12 and start engine. Before releasingstart switch move the battle short switch to the ONposition to by-pass the low oil pressure cut-out switch.(b) If there is sufficient pressure fromthe oil pump, Gil should be forced out of the rockerarm shaft above each cylinder. If there is no evi-dence of oil flow at these points, the oil pump hasfailed. Stop the engine and proceed with the removaland repair procedures.b. RemovalandDisassembly.(1) Drain fuel system and remove main fuel(2) Remove electric starter, tool box andfuel-burning heater if installed. Refer to Operatorand Organizational Maintenance Manual(3) Open oil pan drain valve and allow oilto drain.(4) Close valves for coolant inlet and outletto the engine block if a winterization kit isinstalled.(5) Disconnect coolant inlet and outlet linesto oil pan heater element if winterization kit is installed.Refer to TM 5-6115-545-12 for winterization kit.(6) Disconnect oil drain hose.(7) Refer to figure 14-30 and remove anddisassemble the oil pan and heater as follows(a)Remove 32 capscrews and lock-washers securing the oil pan to the flywheel housing,timing gear cover, and the cylinder block(b)Jar the oil pan loose, drop the rearend, and remove pan.(c)Remove the brass fittings from theinside and Outside of the connections on the oil pan.(d)Remove the nuts, lockwashers, andcapscrews securing the heater element clamps tothe inside of the oil pan.Remove the heater element(8) See figures 14-31 and 14-32 and re-move and disassemble the oil pump as follows:(a)Remove the clamp supporting theoil suction tube.(b)Uncouple the brass compressionfitting securing the oil pump discharge tube.(c)Remove the bolts securing the oilpump to the cylinder block and remove the oil pumpassembly. The pump may have to be pried off itsmounting dowels.(d)Remove the oil pump suction tubesupport bracket from the main bearing cap.(e)Wash the oil pump assembly incleaning solvent, Federal Specification P-D-680.(f)Remove the suction tube assembly.(g)Remove the pressure relief valveassembly from the pump body.(h)Depress the relief valve spring andretainer with two screwdrivers or on improvisedtwo-prong tool.Drive out the roll pin and removeretainer, spring and relief valve piston.(i)Remove the oil pump drive gearfrom the drive–shaft. Use a three-leg puller toavoid damage to the gear.(j)Remove the screws and washerssecuring the pump cover to the body assembly andremove the pump cover.(k) Remove the pump driver gear andChange 614-65tank.
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business