For a car to deliver the best of its performance, it is vital that its engine remains healthy and for an engine to deliver the best output, it is vital that it is fed with the right engine oil. The engine oil is the main food of the engine and it functions as a lubricant, coolant, and cleaner to ensure that the engine functions optimally. In this article, we learn about engine oil, its types, and how you can choose the best engine oil for your car.
Why is engine oil required?
Just like a vehicle cannot be driven without fuel, an engine cannot function without engine oils. The reason is simple. An engine is a cluster of multiple parts that operate in tandem and when these parts function together, friction is generated and it takes only a few seconds for heat to rise above workable temperatures. To keep the friction in check and prevent overheating, the engine is supplied with engine oil. Along with reducing friction and cooling the parts, the engine oil acts as a cleaning agent and cleans the engine by flowing out the sludge and contaminants.
Important Engine Oil Terms
In order to choose the right engine oil for your car, you need to familiarise yourself with some key terms that categorise the engine oils.
Engine Oil Standards – ACEA Oil Standards
To put it in a nutshell, ACEA is an advocate for the automobile industry in Europe and they represent manufacturers of passenger cars, vans, trucks and buses with production sites in the EU. The ‘ACEA’ stands for Association de Constructeurs Européens d’Automobiles, or in English – European Automobile Manufacturers’ Association. The ACEA oil standards are quality indicators of oils, represented by an alphabet and a number, for example, A1. In this, the alphabet indicates the type of engine.
- A – engine oil for petrol engines
- B – engine oil for diesel engines in private cars
- C – engine oil for light vehicle engines with catalytic converters or particulate filters. For example, engines of Light Good Vehicles (LGVs).
- E – engine oil for engines of commercial vehicles and trucks
Meanwhile, the number following the alphabet indicates the performance level of the oil. The higher the number the better the performance.
- Three designations are available for petrol and diesel engines – A3/B3, A3/B4, A5/B5
- Five categories are there for the vehicles with pollution control devices – C1, C2, C3, C4, C5.
- Four categories are there for commercial vehicles and trucks – E4, E6, E7, E9. Among these, E6 and E9 are designed for vehicles with pollution control systems.
Engine Oil Viscosity Grades
Viscosity means resistance to flow or simply, the thickness of a liquid. Therefore, the lower the viscosity the faster the fluid flows. SAE (Society of Automotive Engineers), a global standards organisation has categorised the engine oils based on their viscosities. You must have seen codes like “5W30”, “10W40” etc. on the oil containers. This is a 00w00 format and here ‘W’ stands for WINTER. The number before ‘W’ indicates the engine oil’s viscosity at low temperatures or when the engine is cold. Whereas, the number after ‘W’ indicates the viscosity of the oil at normal operating temperatures, which in an engine is around 100 degrees Celsius. The higher the number, the more efficient the oil is when subjected to high temperatures.
Engine Oil Types
An engine oil is generally a mixture, which has a base oil and some additives to improve the oil’s efficiency. Depending on the oil, its viscosity and efficiency, engine oils are broadly classified into a few types.
Mineral oils
These are the cheapest and crudest engine oils. Produced by refining petroleum oils, mineral oils have some additives mixed and undergo a special treatment to enhance their quality. Generally, mineral oils work fine in most conditions and are mainly used in motorcycles and old vehicles.
Fully synthetic engine oils
Fully synthetic engine oils are the most advanced engine oils and are developed in labs. In their development, the mineral oils are broken down to their basic form. Then it becomes easy to clean all impurities and give a consistent shape and size to the molecules of the engine oil. A lot of chemicals (additives) are mixed in to improve the overall efficiency, and due to such meticulous development, the fully synthetic oils are the most capable in extreme operating temperatures, are the most durable, and offer the longest oil change intervals.
Semi synthetic engine oils
As the name suggests, a semi-synthetic engine oil is a blend of a small volume of synthetic oil mixed with a mineral oil. Therefore, these oils strike a balance between the affordability of mineral oils and the effectiveness of fully synthetic oils. These oils are also known as synthetic blend oils. Meanwhile, semi-synthetic oils are nearly thrice as effective as the mineral oils. Adding some volumes of synthetic oil with mineral oil enhances its viscosity and functionality under a wider range of temperatures and stress.
Factors for Choosing Engine Oil
The engine oil manufacturers have several types of engine oils in the market and all of them differ from each other based on their intended use. Here are some of the factors that will help you select the best engine oil for your car.
Recommended Engine Oil
Usually, the car manufacturers recommend the engine oil in the user manuals of the cars. These recommendations include the ideal viscosity grades and the ideal type of engine for the car. However, most modern engines recommend the fully synthetic oils as they are the most potent ones and make the engines deliver the best of their performance.
Weather Conditions
The weather condition of the place where you usually drive is one of the most important factors influencing your car’s engine performance. If you drive in cold weather, you need engine oil which remains sufficiently viscous in low temperatures. However, if you usually drive in a place where the weather remains hot, you need engine oil which does not get too thin at high temperatures.
With this, driving conditions are also important to consider. If your car encounters start-stop traffic frequently, it increases wear and tear on the engine and in such cases, engine oils with high thermal stability are required. For driving conditions which require higher torque output, engine oils with high detergents and longer-lasting protection should be preferred. At the same time, engines of old cars that are not driven daily can be supplied with mineral oils.
Engine Oil Labels Decoded
We have already explained the engine oil grading system defined by SAE. However, now is the time to learn some popular engine oil grades that are labelled on popularly used engine oils.
5W30, 0W30, etc.
These types of engine oils are suitable for cold climates, because, as can be seen, the viscosity (thickness) at low temperatures is low. This means the oil can easily flow at low temperatures. These engine oils are suitable for cars that are used in places which have seriously cold winters and moderate summers.
10W30, 15W40, 20W50, etc.
As can be seen, these engine oils offer adequate viscosity at high temperatures. Therefore, these engine oils are better for cars that are used in hot weather conditions. If you reside in areas that have extreme summers and moderate winters, these oils are more suitable for your cars.
Mineral vs Synthetic Oil
While synthetic oils are gradually becoming more and more common, mineral oils are still suitable for some cars. However, when we say ‘suitable’ it means just suitable and not the best. Without a doubt, synthetic oils are the best category of engine oils. They offer superior protection, longer lifespans, and long changing intervals. Meanwhile, they are also best for engines that are required to deliver high performance and high fuel efficiencies. The only con of synthetic oils is that they are costlier than mineral oils. But given their quality and calibre, they more than justify their prices.
All the same, mineral oils work fine for old cars or cars with simple engines which usually run at low RPMs. Moreover, since mineral oils are more affordable than synthetic oils, cost concerns can be logical reasons for choosing them. However, if you find the cost of synthetic oils too high, you can consider semi-synthetic oils, which strike a nice balance between the potency of synthetic oils and the affordability of mineral oils.
Popular Engine Oil Brands
Here are some of the most popular engine oil brands in India.
Brand | Oil best known for | Best for |
Mobil 1 | Top-notch synthetic formula and strong protection | High-performance engines, e.g. Sports cars |
Castrol Edge | Titanium technology for stability under pressure and lubrication | Sedans, SUVs, and cars for long-travelling usage |
Shell Helix Ultra | PurePlus technology. Great for mileage. | Daily travellers and highway driving |
Valvoline | Improved wear protection and high-quality detergents | Old cars and off-road vehicles |
Total Quartz | Excellent low-temperature performance | Cold climates and urban usage |
FAQ
How can I choose the best engine oil for my car?
While car manufacturers usually recommend the engine oils in the user manuals, the most suitable engine oil for you depends on the driving conditions. If you live in cold weather, you should use engine oil of grades 5W30, 0W30, etc, whereas if you live in hot weather conditions, you should use engine oils of grades 10W30, 15W40, 20W50, etc. Meanwhile, if your car regularly encounters start-stop traffic, you should use engine oils with high thermal stability, and if your driving conditions need high torque output from your car, you should use engine oils with a high level of detergents and longer-lasting protection.
What are engine oil grades?
Engine oil grades are provided by SAE (Society of Automotive Engineers), a global standards organisation that has categorised engine oils based on their viscosities. These grades follow a 00w00 format and here ‘W’ stands for WINTER. The number before ‘W’ indicates the engine oil’s viscosity at low temperatures or when the engine is cold. Whereas, the number after ‘W’ indicates the viscosity of the oil at normal operating temperatures, which in an engine is around 100 degrees Celsius.
What are the types of engine oils?
Engine oils are broadly categorised into three categories. First is mineral oil, which is the cheapest and is produced by refining petroleum oil. The second is semi-synthetic oil, which has small volumes of synthetic oils mixed with mineral oils. The third is synthetic oil in which a mineral oil is broken down into molecules to make its molecules consistent in shape and size, and then many additives are added to improve their efficiency.
What does the engine oil do?
The engine oil is the lifeblood of the engine as it reduces friction between moving parts, prevents overheating, and cleans the engine by removing sludge and contaminants.
