ELBOW 8C3246 - Caterpillar

The lubrication system consists of a sump (oil pan), oil pump, oil cooler and oil filter. The engine contains an oil manifold and oil passages to direct lubricant to the various components.The oil pump draws lubricant from the sump and forces it through the oil cooler, oil filter, and then into the oil manifold. Oil flows through connecting passages to lubricate the engine components. A regulating valve in the pump body controls the maximum pressure of the oil from the pump. When the engine is started, the lubricating oil in the oil pan is cold (thick). This cold viscous oil does not flow immediately through the oil cooler and oil filter. This cold oil forces bypass valve to open and allows an unrestricted oil flow through the engine and turbocharger.When starting a cold (cool) engine, and until pressure in the lubrication system rises, oil passes through an external line to the bypass valve. The plunger unseats and allows oil to flow directly to the engine oil manifold and turbocharger lubrication supply line. The bypass valve remains open until pressure in the cavity rises. As pressure in the cavity rises, a corresponding pressure increase takes place behind the bypass valve. As oil pressure behind the plunger, combined with mechanical spring force, reaches a value greater than the incoming pressure in the supply line the bypass valve closes; then cooled filtered oil is supplied to the system. The bypass action provides immediate lubrication to all components when cold high viscosity oil causes restriction to oil flow through the cooler and filter. This action is instantaneous when the oil is warm.
FLOW OF OIL (COLD START)The check valve prevents reverse flow from damaging the filter elements when the bypass valve is open. When the bypass valve closes, the check-valve unseats and allows cooled and filtered oil to enter the system.If the oil filter elements become restricted, pressure unseats the filter bypass valves in the oil filter base, and cooled oil continues to flow to the lubrication system.
FLOW OF OIL (NORMAL OPERATION)