You don’t need to be an automotive engineer to know that a car needs an engine to run, but there’s a catch: it can only go places if you keep the engine in good condition. Otherwise, you can’t expect the engine to perform well enough for you to arrive at your destination.
The car engine has many moving parts that need proper care and maintenance, starting with one of the most essential: the engine oil.
You might have a general idea of the need to use engine oil to lubricate the engine, but knowing what exactly it is and how it works won’t hurt either.
This post has got you covered in understanding engine oil from composition and importance down to the most suitable type to use for your car.
The Important Functions of Engine Oil
The moving parts of a car engine are constantly making contact or rubbing against each other, creating friction that can cause heat to build up in the engine. Engine oil has lubricating properties that target the engine’s internal components and the mechanisms supporting them to lessen friction force.
There are two sources of heat in the car engine: the burning of gasoline and friction force. Engine oil tones down the heat while mitigating wear from all the friction. This cycle causes the heat to dissipate out of the engine while facilitating the combustion process.
Protects against corrosion
Engine corrosion is usually the result of oxidation, a chemical reaction where the oxygen from the environment mixes with the engine cylinders made of iron-based metals. Engine oil forms a barrier around the cylinder to avoid getting into contact with oxygen to neutralize this reaction.
Cleanses byproducts of combustion
As fuel undergoes combustion, it produces byproducts such as carbon oxide, nitrogen oxide, and sulfur oxide. These byproducts of combustion may be deposited in the piston ring groove and piston top land causing liner polishing and blowby. Engine oil cleansing additive carries these byproducts in suspension down to the oil filter where they are trapped.
Types of engine oil
Engine oil is classified into three main categories, with each type catering better to specific vehicles’ requirements. Here’s how the oils stack up in terms of composition, viscosity range, and other relevant qualities:
Also known as conventional oil, mineral oil is considered the very first form of engine lubricant. This oil is extracted from crude petroleum and then undergoes a series of refining processes to eliminate impurities.
Mineral engine oils primarily consist of highly combustible hydrocarbon molecules and are often used to break in new cars as they are rolled out of the assembly line.
This type of oil offers essential protection against friction to the engine, so it does not generate as much lubrication as needed when temperatures reach high levels. This makes conventional oil ideal for easy driving of cars with basic engine designs.
Although mineral oil has an affordable price range, frequent oil changes at around 5,000 kilometers may be necessary to prevent engine wear. This oil is usually available in 10W-30,15W-40, and 20W-50 grading variants
This is the mid-ranger in the engine oil categories, which combines conventional engine oil and synthetic oil. As such, this oil does a better job of protecting the engine against potential wear compared with conventional oil. This also means fewer oil changes, which is something you’d welcome since synthetic can be a tad pricer.
The most common oil grades for this type include 5W-30 and 10W-40. It is suitable for cold starts and remains efficient as the engine reaches various running temperatures.
Fully Synthetic Oil
As the name implies, this type of engine oil is fully synthesized. That means it’s developed in a laboratory using a blend of chemicals designed to give everything that you want for your engine: powerful performance, maximum efficiency, and optimum protection against damage.
You can easily identify fully synthetic engine oil, as it bears the ratings of 0W-20 and 5W-30. These ratings ensure excellent cold engine starts while quickly reaching the engine parts even in freezing temperatures.
With fully synthetic oil, your engine can go as far as 10,000 kilometers before requiring an oil change.
Of course, enjoying all the benefits means preparing yourself to pay more for fully synthetic motor oils.
What is engine oil made of?
Modern engine oil is made of base oil and additives. These additives perform various functions—cleaning the engine, reducing friction, lubricating engine components, and more. Here’s the lowdown on the composition of engine oil.
This additive works on high-temperature areas of the engine, such as the piston ring and the crown under the piston where deposits can settle. Detergents also prevent acids from forming in the oil and have the same shelf life as engine oil.
Working hand in hand with detergents, dispersant additives clean the engine by preventing contaminants from mixing with the oil. As such, they help minimize sludge from settling on the engine’s internal components.
This type of additive reduces friction and heat by forming a protective coat on engine surfaces to prevent them from becoming worn out. Anti-wear additives make high-temperature and high-load conditions manageable for the engine.
Air bubbles are prevented from getting into the oil thanks to anti-foam additives. This function is crucial, as foam causes the oil to lose its ability to lubricate vital engine components and keep excess heat at bay.
Also called antioxidants, the purpose of this additive is to increase the oxidative resistance of the lubricating oil since oxidation can lead to oil thickening and sludge formation. Oxidation inhibitors also enable the oil to operate even at high temperatures.
Viscosity index modifiers
Viscosity index refers to an oil’s ability to resist temperature changes. The higher the viscosity, the better the oil coats engine parts to protect them from wear. Besides improving engine or motor oil’s viscosity index, these polymers enhance the dispersing, antioxidation, and anti-wear properties in lubricants..
How to Understand Engine Oil Grade/Specification
If you look at the engine oil label, you’ll see that it has a corresponding SAE (Society of Automotive Engineers) grade. Based on this rating, you’ll know the oil’s viscosity index (VI), which refers to how thin or thick it is. Low viscosity means a thin consistency, while high viscosity gives oils a thicker consistency. Oil viscosity is typically measured at 40° Celsius (104° Fahrenheit) and 100° Celsius (212° Fahrenheit).
As a general rule, engine oil has to be kept as thin as possible in cold temperatures and, conversely, as thick as possible in hot temperatures.
However, the change in viscosity should stay within an ideal range, which the VI indicates. This makes understanding viscosity grades crucial to ensure your engine oil is capable of operating under different conditions.
It’s important to note that a higher VI means minimal viscosity changes, making the oil more effective at protecting your car engine.
Engine oil grades are labeled in alpha-numeric codes, such as 0W-20. The first number includes the letter “W,” which stands for “winter” to indicate the oil viscosity in cold temperatures or at start-up, while the last number indicates the oil viscosity at 100° Celsius (212° Fahrenheit).
The “20” indicates the viscosity characteristic of the oil when the oil is at high temperatures. An oil with a higher viscosity (one with a higher value) may be better suited if the vehicle is operated at high speeds, or under extreme load conditions.