It is normal for each car owner to keep track of any changes in his car. Unfortunately, they are rarely directed for the better, as the parts wear out, rubber products harden, gaskets also lose their properties.
All these liquids are called “consumables”, because over time during operation they are consumed, hence the name. Many may claim that oil is not consumed. This is far from the case. Each engine has a normal oil consumption, which, on average, is a quarter liter per 1000 kilometers.
Increased oil consumption indicates a leak, or, about the wear of some parts. In the first case, it is not difficult to find, and the elimination is reduced only to the replacement of sealing parts and gaskets. The second case is a little worse; it can become a considerable gap in the family budget.
Oil consumption can be increased if it enters the combustion chamber and is mixed with a combustible mixture. Naturally, from this its octane number becomes much less, as a result - a decrease in performance. In principle, engine oil does not burn out, it remains only soot on the parts, and what has not become soot goes out along with the exhaust gases into the exhaust system
Thus, on the one hand, a large oil consumption leads to an increase in toxicity of emissions, and on the other hand, it is deposited on parts, including valves, after which they are not completely closed, as a result of which the compression in the cylinders drops, which means that the engine does not Develops full power.
But these are all the consequences, now a little about the causes themselves. Oil consumption, like fuel consumption, directly depends on the degree of wear of parts. As mentioned above, it grows due to getting into the combustion chamber. There are two ways to do this: either it remains on the cylinder walls, after moving the piston to bottom dead center, or with a combustible mixture through the valves.
So, the first case is the wear of the piston rings, since the oil scraper rings do not cope with their direct purpose. Typically, such a malfunction is accompanied by reduced power at low speeds, as well as increased smoke from the exhaust pipe. Each unit is equipped with crankcase ventilation. Gases from it are fed into the intake manifold for heating the combustible mixture. In addition, everything that "did not burn out" for the first time is submitted repeatedly. So, to determine the wear of the piston rings, it is enough to remove the pipeline from the crankcase to the manifold, which is popularly called "sopun".
The second case is a consequence of the hardening of the valve stem seals that are worn on the valve guide bushings and act as oil seals. In essence, they remove oil from the valve stem when it is opened.
From the above it follows that in order to keep oil consumption within an acceptable framework, piston rings and valve stem seals must be changed in a timely manner , and in order to reduce their wear, it is necessary to change the oil itself in time, which eventually loses viscosity and lubricating properties.