When is it necessary to change the oil? – enginegeek.online

“Changing the oil is a waste of money, caused by the deception of big oil producers. I drove my car for 350 thousand km without changing the oil and nothing happened. And the fact that it turns black is due to soot, which has excellent lubricating properties.”

This short message was announced to the world by Henk de Groot, director of the Dutch division “Castrol”, according to the portal autobild.lt. At the same time it is added: H. de Groot actually held this position, only that he finished his work at the Castrol company 40 years ago.

It is unclear whether the former director received that 350,000. km he traveled with a car (it would be a little strange), or in his entire life, but it is known that after leaving Castrol he developed a sensor that was supposed to monitor the quantity and quality of engine oil and inform the driver about it. However, car companies did not dare to buy his invention.

How does the oil change?

According to oil specialists, carbon black has really good lubricating properties. However, this does not mean that the oil improves the more we use it. The oil turns black because fuel combustion products, including soot, get into it. The color changes especially quickly in diesels.

One of the properties of oil is the decomposition of soot particles. As the oil ages and absorbs more and more combustion products, the number of healthy alkalis (TBN) in it decreases, and at a certain point the oil stops “swallowing” the newly formed portions of soot. The result is deposits and sludge on engine parts.

Due to the high amount of soot, the oil becomes less resistant to extreme temperatures. True, it still effectively lubricates the rubbing parts, but ceases to protect them from corrosion. There may also be problems with the “transport” of oil: due to long operation, its viscosity increases and in many places (for example, the channels of the engine cylinder head) too little enters. Meanwhile, if the viscosity decreases (the oil becomes thinner), the lubrication also becomes less effective.

Engine maintenance intervals are calculated with 10%. reserve Therefore, if we use the car in average conditions, we will not cause a catastrophe if we take a little while to change the oil. The situation is very different when the engine’s working conditions are difficult (high loads, very cold or hot climate, etc.): in this case it is necessary to change the oil more often. In other words, how quickly the oil stops applying properly depends on the driving conditions.

Castrol statement:

“The person whose statement that it is not necessary to change the engine oil is quoted in the press and on the Internet has not worked for Castrol for several decades. The company does not agree with the quoted opinion of this person. We would like to point out that the frequency of changing the oil and other operating fluids is decided not by the manufacturer of these products, but by the vehicle manufacturer.”

What happens if you don’t change the oil on time?*

*in cars where it is recommended to change the oil every 15,000 km. km

0km

New oil is clear and ready to absorb dirt. Viscosity and other parameters generally exceed the norms indicated on the package: the best oils have a greater “reserve”, the worst oils have a smaller one.

10,000km

Discolouration: Visible darkening is seen in petrol engines, although the oil remains clear in cars with LPG equipment. In diesel engines it is already black, but that does not mean it needs to be changed.

15,000 km

A decrease in the number of alkalis, a high percentage of fuel combustion products. The oil is diluted with fuel, its viscosity changes, but the protective properties are still retained.

Recommended replacement

20,000 km

The ability to break down soot ends: it settles on engine parts and oil channels in the form of slag. In LPG engines, acidic combustion products cause corrosion. After adding new oil the situation improves slightly.

30,000 km

When starting the car, the oil does not penetrate into hard-to-reach places, at extreme temperatures parts subject to heavy wear are not protected. The oil channels become clogged with soot, the distribution system has high friction.

60,000 km

At any time the engine or turbine can “stick”, the engine runs noisily. Increased friction causes the timing belt or chain to break. In this case, the engine will need to be repaired immediately.