The correct amount of engine oil is an absolute axiom for the longevity of any engine, but despite this, the question of the ideal level continues to cause controversy among drivers. Two extremes are common: some are convinced that the maximum mark provides the best protection, while others risk driving, literally “in the red“. The truth, as usual, lies in the middle: both a shortage and an overfill with lubricant are equally destructive for the engine.
Oil starvation
When the oil level drops below the permissible minimum, the engine is at risk of “oil starvation“. At this critical moment, the oil pump begins to suck in air instead of lubricant. This leads to a rupture of the oil film between the rubbing components, while the temperature inside the unit rises sharply. The components begin to work “dry”, which leads to catastrophic wear.
The situation is especially difficult with turbocharged engines. The turbine, operating at extreme temperatures, quickly overheats and is irreparably damaged. It should be remembered that in addition to lubrication, oil also plays a critical role in cooling the hottest components, and even the perfect antifreeze cannot compensate for this omission.
Overfilling
Paradoxically, too much oil is no less destructive. Excess lubricant falls under the blows of the crankshaft, which leads to intense foaming. Once foamed, the oil loses its lubricating properties and creates excess pressure in the crankcase.
This pressure seeks an outlet, which inevitably leads to leaks through seals and oil seals. In addition, foamed oil can contaminate the throttle valve and even penetrate the intake manifold.
In diesel engines, overfilling is the greatest danger: in rare but terrifying cases, oil can be sucked into the intake tract and start burning like fuel. This causes an uncontrolled increase in rpm, known as runaway, which is almost certain to doom the engine.
Again, turbocharged engines suffer more here: excess can lead to deposits in the hot part of the turbine and in the intercooler, which reduces pressure and ruins seals.
The perfect point
To avoid this double risk, the oil level must be strictly maintained within the operating range of the dipstick. The optimum point is clearly defined: exactly halfway between the minimum and maximum marks, or slightly above the middle.
This level has been confirmed as ideal by leading mechanics and engineers around the world. It ensures flawless operation of the system in all load modes and, importantly, leaves enough room for thermal expansion of the oil when it warms up to operating temperature.
Regular level monitoring – recommended every 1-2 weeks, especially during the cold winter months – is the simplest and cheapest way to ensure the long life of your engine and avoid extremely expensive repairs.