Best 10w40 Oils of 2021

10w40 Oil – Buying Guide, Opinions and Analysis


If you want to get maximum performance from your car engine, then you will have to lubricate it properly. In this way, a protective cover will be created on the gears, which will prevent wear generated by friction after start-up. Thus, it is possible to extend the life of the machinery. For example, Castrol GTX Ultra Clean is a semi-synthetic 10w40 oil, suitable for gasoline and diesel cars, whose five-liter presentation is available in a robust, easy-to-handle container. For its part, Motul 4100 Performance oil has a synthetic formula that can be used in old and modern cars.


Shopping guide


Taking care of your car’s engine is a simple task that you cannot neglect, and that begins with proper lubrication of its mechanical parts. To do this, it is necessary to use an oil that is adapted to the specific needs of each car, which gives it better performance on any terrain without causing wear to the gear series. Here is a guide to buying the best 10w40 oil.



The composition of the product is one of the aspects that cannot be omitted from any 10w40 oil comparison, due to its high level of importance in the operation of the engine. Therefore, the implementation of the wrong formula could seriously impair the performance of the machinery.

The important thing is that you know how to identify which is the right composition for the car. In this sense, you will find monograde motor oils that are of natural origin and have a single level of viscosity. For their part, multigrade lubricants are manufactured with chemical chains, capable of offering specific properties for each type of car.

In fact, this last type of composition allows maximum performance, both in the city and on long trips, when going on vacation, because the formula adapts to low and high temperatures, for an effective cold start, without deteriorating the components. the motor.



The viscosity of the oil used in the car engine is of great importance for the correct functioning and care of the internal parts of the car, so we cannot select it at random, if we do not want to reduce the performance of the machinery. In addition, the issue of lubricant density is an aspect that, in most cases, influences how much the product costs.

Always bear in mind that the viscosity of this type of oil is determined by a numerical scale and a letter that, according to the nomenclature, corresponds to the type of starter offered. For example, oils designated with the acronym “W” indicate a cold start, being the case of 10w40 lubricants. Therefore, you should review the specifications of the car, to get the right product for your needs.

In the market, you will find low and high density oils suitable for use in gasoline or diesel cars. These products, when incorporated into the motor, create a millimetric protective film between the gears, to prevent wear due to friction. In addition, they improve the performance of the machine in the most extreme conditions, without straining the mechanical components.



The container of the motor oil to be purchased is an aspect that many people leave unnoticed, but that, in reality, has great importance, since it is the structure that contains the lubricant and we will have to manipulate it to fill the engine. Therefore, it is not only necessary to get an economical product, but also an ergonomic and safe container.

In general, manufacturers of 10w40 oils use cans made of robust and slightly flexible polymer, which will hardly break after an impact. In addition, these structures incorporate a superior or lateral grip area with an ergonomic and non-slip format, designed in this way so that you can comfortably hold the container, both when pouring the product and when transporting it.

Likewise, these cans have been provided with a reduced mouth, to extract the oil moderately, while the screw cap and the seal in the form of a plug, preserve the good condition of the oil and prevent spillage, in the event of an unexpected tipping when manipulate the boat.


Environmental care

The quality of the 10w40 oil purchased is of great importance, not only for proper motor operation, but also for caring for the environment. Remember that, after the engine is started, a combustion process is generated in which all the waste that accumulates in the filter is incinerated, which immediately generates an emission of carbon monoxide, which pollutes the air we breathe.

In this sense, more and more brands are betting on the manufacture of synthetic lubricants, since in this way they can create special formulas capable of enhancing the control of toxic emissions. Thus, it is possible to significantly reduce the high volumes of contamination common in conventional oils.




Frequently asked questions


Q1: How to use 10W40 oil?

To use 10W40 oil, you need to start by checking the lubricant level in the engine tank, so you will have to remove the dipstick, clean it with absorbent paper, insert it again and remove it to know the exact measurement. Remember that the rod has a small mark, which is used as a reference for measuring the liquid.

Then release the cap from the reservoir set for the oil, pour it carefully and wait at least five minutes. In this way, you can repeat the initial procedure with the dipstick, to check that the oil has reached the regulatory measure for proper engine operation.

It is important that, during this task, the car’s machinery is turned off and completely cold. Otherwise, the person could experience some type of burn, due to the bad handling of these areas of the car.


Q2: Every how many km is the 10w40 oil changed?

Changing the engine oil is a task that must be performed periodically. In this way, you will be able to take care of the useful life of the mechanical parts and enhance efficient performance. According to automotive experts, the scheduled time for the change could depend on the type of car, as well as the lubricant used.

For example, if you are one of the users who use mineral oil, you will have to change it after three thousand kilometers of travel. For their part, those who opt for oils with a synthetic formula, will be able to enjoy a maximum of six thousand kilometers of travel, before carrying out the oil change. Finally, if you pour 7100 full synthetic lubricant into the engine, you will have to change it after about 10,000 kilometers.


Q3: What is the basis of 10w40 oil?

The 10w40 oil, both synthetic and semi-synthetic, has as its main base refined crude oil. However, the first one is exposed to a laboratory process, in which the molecular level of the formula is changed through chemical processes.

In this way, a significant improvement is achieved in the results obtained when using it. For example, you will enjoy adequate temperature control and various levels of density, for better protection against the wear of mechanical components.

For their part, semi-synthetic lubricants or also known as monogrades, add to the previously mentioned petroleum base, some mineral additives. Therefore, its formula only offers one level of viscosity.


Q4: What temperatures does 10w40 oil withstand?

With regard to the temperature supported by semi-synthetic or multigrade 10w40 oil, it is important to note that it is suitable for climates that exceed 38 ° C and offers a smooth start from -30 ° C, while the synthetic or monograde models start from 10 ° C onwards.


Q5: Which oil is better, 5w40 or 10w40?

Both 5w40 and 10w40 motor oil are high-quality products, but they do have some significant differences, which could influence engine performance in different scenarios.

For example, the 5w40 lubricant has a synthetic composition suitable for sports cars and, according to experts, its use is recommended for short trips, preferably within the city.

For its part, 10w40 oil is a semi-synthetic formula, which is convenient to be used in small cars, fulfilling long trips on the road, without causing deterioration in the mechanical parts of the engine due to its high level of viscosity.

In fact, the density of both lubricants is one of the main differences between them, since, according to the 5w40 and 10w40 nomenclature, the first number indicates the viscosity; the lyrics, the cold start; and the last number, the temperature. In other words, the 5w40 is lighter than the 10w40.


Q6: Where is used 10w40 oil thrown away?

Once the engine oil change is finished, you should take care of the extracted lubricant, since it is a highly polluting substance, which we should not throw away anywhere.

In this sense, it is important that you consult the official page of the brand used and investigate where the clean oil collection points are located. In this way, you can help in the recycling process of this type of compound, taking said substance so that it receives the appropriate treatment and is regenerated, decontaminated or materialized.

Thus, this residual oil will be used to manufacture new products for industrial plants or as part of the raw material necessary for asphalt, waterproof fabrics, among others.


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