To what level on the dipstick should engine oil be added?

[LePaige]

Engine oil should be added to a level between the upper and lower marks on the dipstick. If there is too much lubricating oil, it can seep into the combustion chamber through the gap between the cylinder and piston, forming carbon deposits. These deposits can increase the engine's compression ratio, raising the likelihood of knocking. Additionally, carbon deposits in the cylinder, when glowing red-hot, can lead to pre-ignition. If they fall into the cylinder, they can accelerate wear on both the cylinder and piston and also contaminate the lubricating oil more quickly. The dipstick is a commonly used tool for checking the oil level in the lubricating oil reservoir. Due to the curved path of the dipstick tube, the dipstick must be able to deform when inserted and rebound to its original shape when removed. The engine lubrication system includes the oil storage system, oil distribution system, and oil indication system, among others.

[McPresley]

I usually check the engine oil on level ground, waiting about ten minutes after turning off the engine to let the oil settle. I pull out the dipstick, wipe it clean with a paper towel, then fully reinsert it and pull it out again to check. The ideal level is within the middle range of the markings, usually clearly indicated between the upper and lower limits. If the oil reaches near the MAX line, no additional oil is needed. It's normal for the level to be higher when the engine is cold, as it will drop when warm. Some cars have a small gap between the upper and lower limits, so if the level is close to the upper limit, even if it hasn't reached the line, no extra oil is required. It's best to develop a habit of regular checks, like taking a quick look before each refueling, especially for cars frequently used for long trips.