How much difference can the oil on the dipstick be after the cold car and the hot car are turned off?

After the cold car and the hot car are turned off, the difference between the oil on the oil dipstick is about 3~7 scales.

This is because when the car is cold, the oil will completely settle down. When the car is on fire, the oil is taken to all parts of the machine that need lubrication to work. Therefore, the oil has not completely returned to the bottom of the car that has just stopped, and the oil gauge will be lower than when the car is cold.

Engine oil consists of base oil and additives. Base oil is the main component of lubricating oil, which determines its basic properties. Additives can make up for and improve the shortcomings of base oil properties and give some new properties, which is an important part of lubricating oil.

Extended data

Engine is a special kind of machinery, and its requirements for lubricating oil have its own special side, and its particularity mainly includes:

1) The general requirements for the engine are small volume, light weight, compact mechanism and high output power, so it bears a great load on the unit friction surface.

2) Besides the friction heat, it is also affected by the combustion heat, so the temperature of the friction surface is very high, which reduces the viscosity of the lubricating oil and is not easy to form an oil film.

3) The high-temperature and high-pressure combustion gas in the combustion chamber will leak into the crankcase through the gap between the piston, piston ring and cylinder liner. These combustion gases are gases and some particles (smoke and dust) produced by complete combustion and incomplete combustion of fuel oil and a small amount of lubricating oil, which usually become the main components of crankcase blowby, and will pollute lubricating oil and promote its oxidation under certain conditions.