SEAL-O-RING 1214344 - Caterpillar

The lubrication system uses an externally mounted engine oil pump that is located on the front left side of the front housing. Engine oil is drawn from the sump through the suction bell and a tube by the engine oil pump. There is a strainer in the tube between the suction bell and the tube.The engine oil is pumped to the priority valve and the centrifugal oil filters.The priority valve's relief valve opens in order to divert the engine oil back to the sump when the engine oil pump's pressure exceeds 1000 kPa (145 psi). This helps prevent damage to the lubrication system components when the engine oil is cold.The priority valve's bypass valve opens in order to divert the engine oil back to the sump when the system's pressure in the main engine oil gallery exceeds 430 kPa (63 psi).Engine oil is also pumped to the engine's oil temperature regulator housing. If the engine oil temperature is higher than the rating of the temperature regulators, the flow will be directed to the engine oil coolers. Engine oil flows from the engine oil coolers to the engine oil filters. The engine oil then flows through the priority valve to the engine oil galleries in the cylinder block.Prelube Pump
The prelube pump is driven by an electric motor or by an air motor. The prelube pump provides engine oil for lubrication of the engine's bearings before start-up and during service procedures when the crankshaft is rotated.A one-way check valve is located in the tube between the prelube pump and the engine's oil manifold. The check valve prevents pressurized engine oil from flowing back to the prelube pump after the engine is started.