General description of the engine lubrication system (VW Beetle)

The engines of the vehicles described have a forced circulation lubrication system with a gear oil pump, a mesh oil filter and an oil radiator. The oil pump is directly connected to the camshaft and driven by it. The pump draws oil through a screen from the oil sump and forces it through the oil cooler into the oil passages.

The relief valve, installed in front of the oil cooler, regulates the flow of engine oil through the oil cooler depending on the oil temperature. When the oil is cold and viscous, the valve piston is closed. The oil flows directly to the lubrication points, some of it returns to the crankcase. As the oil temperature rises, its pressure drops, and the piston of the safety valve gradually closes the direct path to the lubrication points. The oil passes partly through the radiator and partly directly to the lubrication points. When the engine is hot, the valve piston moves to its highest position. In this case, oil is supplied to the lubrication points only through the oil radiator.

At the end of the crankshaft there is a bypass valve that stabilizes the oil pressure. It opens at a pressure of 2.8 bar (atm).

The original information is posted on the resource: vwmanual.ru