Behind the oil filter is a relief valve that maintains the oil pressure at approximately 4 bar. At higher oil pressure, the valve opens and some of the oil can flow back into the oil pan.
The main oil line has channels for lubricating the crankshaft bearings. Through inclined holes in the crankshaft, the oil is directed to the connecting rod bearings, and from there it is sprayed onto the piston pins and cylinder walls.
At the same time, oil is supplied through the intake pipes to the cylinder head to the camshaft bearings and valve drive clearance compensators (hydraulic tappets) and to the valve guides. The presence of check valves in the line always guarantees a sufficient amount of oil to lubricate these parts in the cylinder head.
In addition, the camshaft drive chains are lubricated, and in the case of a 6-cylinder petrol engine, the oil pump drive chain is also lubricated.
Oil consumption
In relation to an internal combustion engine, oil consumption is understood as the amount of oil that is consumed as a result of the combustion process. In no case should oil consumption be equated with oil loss that occurs due to leaks in the oil pan, cylinder head cover, etc.
Normal oil consumption occurs due to combustion in smaller quantities, depending on the circumstances, in the cylinder, as well as due to the removal of combustion products and wear particles. In addition, the oil ages under the influence of high temperatures and pressures, to which it is constantly exposed in the engine. In addition, external operating conditions, such as the driving mode, as well as manufacturing tolerances, affect oil consumption. The highest oil consumption should not exceed 1.5 l / 1000 km.
Caution: Under no circumstances should the oil level in the sump exceed the Maximal mark on the dipstick. If too much oil has been added, the excess must be drained. Otherwise, the catalytic converter may be damaged, as unburned oil gets into the exhaust system.