Choosing the best engine oil for your car
To permanently lubricate a vehicle’s engine, you obviously need a quality oil. You should not use just any oil, because it is specific to each car. In addition to helping keep the engine clean, the oil will also help cool it and prevent wear and tear on all of the parts that make it up. It is therefore important to choose the right oil to ensure optimum engine operation and longevity. The viscosity index, the engine is all criteria to consider when buying the engine oil that will be used for changing a car.
Engine oil: what role does it play?
Engine oil is essential for lubricating the various parts of the engine and thus keeping it clean. Quality oil will considerably limit engine clogging. But, that’s not his only role. It is also useful for limiting the friction that causes engine wear. Engine oil will also decrease the temperature of the latter thanks to its role as a coolant. It will indeed allow the evacuation of mechanical heat caused by the friction of the parts as well as the combustion of fuel. The latest generation engines are able to reach high temperatures in terms of their segmentation. This technical fluid will also protect against engine corrosion.
There are 3 main categories of motor oil: 100% synthetic oils, semi-synthetic oils and mineral oils. The former, which are tailor-made to meet prescribed chemical and physical parameters, represent the very best in engine oil quality, and the latter is the most affordable. Finding a good quality motor oil for your car can be a real headache because of the many brands currently on the market. Not to mention the many references, codes and standards that can be read on the oil cans. However, certain factors can guide consumer choice.
Best engine oil
The engine viscosity index
The viscosity index is always indicated on the motor oil cans. It generally corresponds to a succession of numbers and letters (for example 5w40, 10w40, 10w30 oil, etc.). The first number is used to indicate the fluidity of the oil or its cold viscosity. The oil is more fluid if the index approaches 0. The second number indicates the hot viscosity. Oils offering excellent protection at high temperatures are those with a high hot viscosity index. They thus promote engine protection as well as the sealing of the segmentation.
Synthetic, semi-synthetic or mineral motor oil?
Not all engine oils are of the same quality. To ensure the longevity of your engine, it is, therefore, necessary to choose the right lubricant.
100% synthetic oil (full synthetic oil)
Synthetic motor oils are obtained from the distillation of crude oil or synthetic oil to which additives have been added. The latter’s role is to compensate for the weakness of the base oils or to optimize their fundamental properties. 5w30 oil and 5w40 oil are part of the category of so-called synthetic oils.
These are the oils that are typically used in recent engine models, whether they run on diesel or gasoline. On cars equipped with a particulate filter, it is mandatory to switch to 5w30 synthetic oil. It is also recommended that motorists who tend to over-force their engine, such as sports driving enthusiasts or those who make a lot of restarts or stops frequently to use this oil. Indeed, 100% synthetic oils allow easy cold starting of the engine. In terms of cost, these oils seem particularly suitable for heavy-duty riders thanks to the fuel savings they can provide.
In addition, with these engine oils, the oil change intervals are much longer. For the most recent diesel cars, the oil change can be spaced up to 30,000 km, compared to nearly 15,000 km for gasoline vehicles. Note that the use of 100% synthetic oil on older engines may affect the seal of the segmentation, and is therefore not recommended.
10w40 oil is one of the semi-synthetic oils. It offers an excellent level of wear protection and makes cold starting the engine easy. Oil changes will however be more regular, ie every 10,000 km on average for diesel cars. Motorists who do not drive a lot or who do not put a lot of stress on their engine can easily turn to this oil, which indeed offers good value for money.
Mineral motor oils
The 15w40 oil, which is mineral oil, is recommended for old vehicles running on gasoline, that is to say, those which are more than 12 years old, but also for diesel cars without turbo. It is thicker and therefore suitable for vehicles requiring high oil consumption. Oil change intervals should be shorter when using mineral motor oil, however, as it tends to lose its lubricating capacity quickly.
Engine oil standards or their approval
The best motor oils also meet certain standards imposed by certain independent organizations, such as ACEA, whose mission is to qualify their anti-wear and antioxidant performance. It is thus advisable to choose the one which will be adapted to the motorization of its vehicle. The standards are generally indicated on the back of the cans.
The ACEA, or Association of European Automobile Manufacturers, has established a classification standard for engine oils:
- Standard A is recommended for petrol engines
- The B is suitable for diesel cars
- The C is for vehicles fitted with catalysts and particulate filters
- The D is recommended for commercial vehicles and heavy goods vehicles.
These standards are associated with 3 performance levels: level 1 for economical use, level 2 for normal use and level 3 for intensive use. For example, you can find the “ACEA A3 / B4” standard on an oil container. In addition to the ACEA standard, there are also the API (American Petroleum Institute) and SAE (Society of Automobile Engineers) standards.
All you have to do is refer to the vehicle’s user manual to find out the standard recommended by the manufacturer. In order not to be mistaken, you can also seek the advice of an automotive professional. In fact, you don’t have to blindly follow the advice given by your manufacturer, because the latter can work in partnership with engine oil manufacturers, and can thus favor a particular brand. However, it remains important to take into account the manufacturer’s recommendations.
Which brand of engine oil to choose?
As long as you know the viscosity index and the standard that corresponds to the engine of your car, you just have to choose the oil that fits your budget. The brands that offer it are legion today. The key is to compare the prices and the nature of the oil.
In general, full synthetic oil will be the most expensive because their manufacturing cost will be higher than that of semi-synthetic or mineral oils. To design high-performance oils, manufacturers rely on additives that optimize their properties. These additives will notably increase the level of protection against wear and corrosion. They will also give certain properties to engine oil such as resistance to oxidation (thanks to antioxidant additives), the dispersion of pollutants, etc. You have the choice between different ranges. Oils with the most additives are generally the best performing, and therefore the most expensive. Choosing major brands like Total, Elf or Castrol is therefore a safe bet regardless of the type of engine oil chosen.
Any other specifics to take into account?
In addition to viscosity levels and standards, the choice of engine oil can also depend on other factors. In fact, you can find many oils with the same level of viscosity. To make a decision, one must also take into account the age of the vehicle, its engine (diesel, gasoline, turbo, etc.) as well as the user’s driving style. The type of oil chosen will not necessarily be the same if you are used to driving in the city or mainly on the highway. Synthetic oils will be recommended for sporty driving while semi-synthetic oils will be ideal for driving in urban areas. Occasional drivers may be satisfied with mineral motor oil to keep their engine in good condition.
When should you change your engine?
It is necessary to regularly drain your engine with the best possible tools (see our article on this subject) in order to guarantee better protection for the engine in question. To know the frequency with which to replace the engine oil, it is necessary for particular to take into account the number of km already traveled since the last oil change as well as the overall mileage of the vehicle.
This frequency will also depend on the type of engine you have (diesel or gasoline with direct or indirect injection, diesel with particle filters, etc.). The engine oil change interval will also vary depending on individual driving habits (city driving, sporty driving, on the highway, etc.).