Can motor oils of the same grade be mixed?

[SanJack]

Motor oils of the same grade can be mixed, but it is not recommended for long-term use. Increased fuel consumption: When adding oil to the engine, the oil level should be between the upper and lower limits on the dipstick. If too much oil is added, the engine's temperature will rise, causing the oil to expand. This increases the pressure in the oil chamber, raises operating resistance, reduces the car's power output, and increases fuel consumption. Overfilling oil: If too much oil is added, the crankcase breather pipe may leak oil, increasing the pressure in the crankcase. This can cause the oil seal to loosen under pressure, leading to oil leaks. Function of motor oil: Motor oil is the lubricant for engine operation. It lubricates, cleans, cools, seals, and reduces friction in the engine.