Why do motorists deliberately pour oil into the engine

Go ahead. Consumption also depends on driving style. Therefore, owners of powerful sports cars also deliberately overestimate the level. It’s not just about the cost of waste. When braking from high speed before a turn, the lubricant in the crankcase drains, which contributes to oil starvation. This is a direct path to the breakdown of an expensive unit. To avoid this effect, some manufacturers even install the so-called rib (anti-overflow baffle). However, we will not develop the topic further. It deserves a separate article.
If we return to conventional t / s, then overflow in some cases will have a negative effect. So the excess lubricant will capture the crankshaft during operation. What will create an oil mist in the crankcase, which will be sucked into the ventilation system. The result is a dirty throttle assembly and a compressor with an intercooler. Hence, such troubles as a drop in engine acceleration and its unstable idling occur.
In the end, we note that you need to carefully drain the excess. If, say, unscrew the stopper of the pallet, then you can remove much more than you need. It is easier to pump out the “slurry” through the dipstick using a thin hose and a syringe (large, the one under the catheter).