TM-9-2815-220-24 Maintenance Manual for AVDS-1790-2CA AVDS-1790-DA and AVDS-1790-2DR Engines Download
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TM 9-2815-220-24 THEORY OF OPERATION 0004 00 ENGINE COMPONENTS (Continued) Oil Coolers, Transmission and Engine: External oil coolers accomplish transmission and engine oil cooling. The oil coolers are located on the sides of the engine above the cylinders. Air is drawn through the oil coolers by the cooling fans. A thermostatic control valve in each oil cooler controls the temperature of the oil from the cooler by permitting cold oil to bypass the coolers. This valve also permits oil to bypass the cooler in the event that the cooler becomes clogged. Oil Pan: The oil pan acts as a reservoir for the oil, and is the base for the cylinder block, thereby forming a strong engine structure. It is a one-piece aluminum alloy casting divided into an oil pump pressure compartment, an oil reserve compartment, and a sump compartment. Cored passages from each of the compartments terminate at a central outlet and permits draining. A separate passage permits draining the oil coolers and oil filter compartment directly without permitting any sludge to enter the oil pan. The oil pan is designed to maintain a constant oil level, above the oil pump pickup tube, regardless of the angle at which the engine/vehicle is operated. Engine Oil Cooler Transmission Oil Cooler Oil Pump: The oil pump provides pressure to circulate oil to engine parts minimizing wear. The oil pump consists of four sections combined in a single unit. The main section (pressure) draws oil from the oil pump pressure compartment in the oil pan. This oil pan compartment is fed by the scavenge section of the pump which picks up oil from the sump compartment at the front end of the oil pan and by oil which drains into the pressure compartment from the cover of the pressure pump compartment and the reserve compartment. The dual inlet make-up section picks up oil from opposite corners of the reserve compartment. The dual inlet feature assures that the inlet to the main section is supplied regardless of engine tilt. The leveling pump section returns any excess oil to the reserve compartment. The make- up section and the leveling pump section work together to maintain a constant level in the main pressure compartment. WP 0004 00-25