The Internet is full of tales about how dangerous an engine oil overflow is. Sometimes they even frighten you with a major overhaul. But what are the risks if you pour lubricant into the motor in excess of the norm and is it dangerous at all? The experts of the Avtovzlyad publication decided to figure out how things really are.
Sometimes in car services, some mechanics deliberately fill in oil above the max mark, especially in cars with increased oil consumption (for example, BMW engines suffered from this at one time). This is done so that the owner does not crawl under the hood once again and does not bother to monitor the oil level, but simply rolls from replacement to replacement.
How can such an overflow be dangerous? In the worst case scenario and a strong overflow, the breather will begin to squeeze oil into the intake tract. As a result, soot will begin to form intensively, clogging the oil channels. As a result – oil starvation and the resulting “capital”.
Also, excess oil will begin to squeeze out through various seals and gaskets, causing characteristic noticeable smudges. Thank God that these processes are relatively not very fast and it is possible to prevent them in advance.
With a small overflow, nothing terrible should happen to the machine. Moreover, oil is slightly poured into sports cars in a special way in order to prevent oil starvation during active driving. Indeed, with intensive “piling”, there may be lateral outflows of grease from the oil receiver. And the oil pump, not having enough oil, will trap air.
Another common misconception is the crankshaft “whipping” oil when overflowing. Allegedly, foam bubbles are formed, falling under the hydraulic lifters and reducing the efficiency of the gas distribution mechanism.
But this, of course, is nonsense – in any modern, even budgetary oil, there will definitely be a package of antifoam additives. In principle, no bubbles should appear in it.
What’s the bottom line? Overfilling, in general, is not as bad as underfilling. In this case, in order to bring the problem to an expensive repair, you will have to try pretty hard. In general, do not forget to monitor the oil level. If underfilling, top up, and when overflowing, you can unscrew the drain plug or remove a little oil with a conventional syringe.