TOYOTA COROLLA car engines have a pressure lubrication system. A nice little pump sucks in engine oil through a suction strainer from the oil pan and pumps oil under pressure through the main oil filter. A pressure reducing valve is installed in the system. When the pressure rises above the set value, the valve opens and drains part of the oil into the oil pan.
After passing through the oil filter, the oil enters the main line. A pressure sensor is installed in the main oil line, which lights up a warning lamp on the front panel of the car when the oil pressure drops below the set value. When the oil filter is clogged, the bypass valve directs the crude oil directly into the lubrication system.
Through branches from the main line, oil enters the bearings of the crankshaft. Through inclined drillings in the crankshaft, oil enters to lubricate the connecting rod bearings.
At the same time, oil through the pipeline enters the cylinder head to lubricate the camshaft bearings, rocker arms and ends of the valve stems.
Some engine designs have an auxiliary oil cooler. Here, part of the oil after the oil pump is sent to the oil cooler located in the front of the vehicle.