Engine oils are one of the most important aspects for an engine to run properly. But there are so many types of oil that they sometimes mislead drivers, and they end up using an oil that is not suitable for their engine, and that will mean quite serious problems in the long run.
Choosing the right type of oil should be the first thing that every driver has to know. The important information of the engine oil viscosity recommended by a manufacturer for a certain type of engine is usually written in the car manual. There you will find very important information regarding all the types of oil that your engine should use.
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The main differences between 15w40 and 5w40
The main differences between 15w40 and 5w40 refer especially to how well these two types of engine oils help the engine regarding the ambient temperature in which they are used. 15w40 can be used in the temperature range of -20 °C or -4 °F and +40 °C or 104 °F, on the other hand, 5w40 is used between -30 °C or -22 °F and +40 °C or 104 °F. So, we can say that 15w40 is better in a warmer environment and 5w40 does a better job in a colder climate.
Also, 15w40 is often used in engines that have more than 60.000 miles because it protects the engine better than 5w40 regardless of the fact that 5w40 has a wider range of use than 15w40 and this is because of its viscosity and the way manufacturers make the motor.
There is also oil that can be used only in summer and in winter. For this, only the second number is present in the summer one, for winter ones, only the first one with the letter W.
Both numbers in the marking indicate that this oil can be used all year round at temperatures that do not go beyond the conventionally designated numbers. Also, manufacturers decided to make only oils that can be used all year round because of the benefit of not changing the oil every time the season changes. This can also be a benefit for the driver because it saves time and money.
The main features of 15w40 engine oil
Oil viscosity grades are primarily recommended according to the expected ambient temperatures, particularly the starting temperatures, as I have mentioned above.
Both oils in question are classified using the standard classification (SAE), both being multigrade oils that can be used in summer and winter because of the letter “W” that they have in their name.
So, according to SAE standards, the parameters 15, W, and 40 mean the following:
- Number 15 indicates the low-temperature viscosity at which this oil type maintains its benefits. For the 15w40, cold resistance is at around -20 °C or -4 °F;
- Number 40 shows the opposite temperature. From the description, 15W40 will retain its protecting properties up to +40 °C or 104 °F;
- The letter W defines the all-season use of the product, this means that the lubricant is used both in winter and in summer conditions.
15w40 oil advantages
- This type of oil suits well cars that have a worn-out engine, because it protects the engine better;
- Prevents the formation of corrosive processes, promotes the removal of sludge;
- Provides more economical fuel consumption in the internal combustion engine, with a high degree of wear.
- The oil is cheaper to make;
- Good for the engine in warmer enviromennt
15w40 oil disadvantages
- Not able to maintain its viscosity if you have a more aggressive driving style and in extreme operating conditions;
- Not the best option to choose at low temperatures, since 15w40 oil loses its characteristics below -20 degrees Celsius or -4 degrees Fahrenheit.
- Some manufactureres don’t recommend the oil for use in the engines.
- Low replacement time interval, not exceeding 5000 kilometers or 3000 miles.
If the air temperature drops below the SAE specification limit, the lubricant’s flow rate will decrease. Due to the increased viscosity of the oil, it will become difficult to start the engine.
But even if the car starts up, the oil thickened from frost will not be able to fill all the gaps between the rubbing units and mechanisms. This, in turn, leads to accelerated wear of engine parts and overheating.
The main features of 5w40 engine oil
Being a multigrade oil, 5w40 can be used regardless of the season, shown by the letter “W” in its composition, having a wider range of use than 15w40. The oil can maintain its protective properties in the temperature range of -30 °C or -22 °F shown by the “5” parameter and +40 °C or 104 °F indicated by the “40” parameter.
5w40 oil advantages
- Due to good cleaning from impurities, almost no deposits occur on the engine.
- Retains its protective properties longer, protecting the engine from wear.
- Helps the engine in a colder enviromnemt better than 15w40, especially when starting the engine;
- Has good heat resistance, thus it can cope with an aggressive driving style and extreme conditions.
The engine oil change frequency for the 5w40 oil is 15000 kilometers or 9000 miles. Being an all-season oil with a fairly wide operating temperature range, 5W40 oil is more suitable than others for cars with similar annual mileage.
5w40 oil disadvantages
- It’s more expensive than 15w40;
- It can be used in engines that are not that worn-out;
- Some manufacturers don’t agree with using 5w40 in their engines;
Final toughts
When choosing an engine oil, first of all, you need to rely on its viscosity. Check with your car manufacturer or read the manual for recommended metrics. Try to avoid adding other engine oils than the ones shown in the manual.
Secondly, it is necessary to take into account the condition of the car and the conditions of its operation. This will help you to choose the correct oil to choose for your car.
