The Science of Oil Additives: How They Improve Performance

Engine oil is essential for keeping your car or machine running smoothly, but did you know that it’s the special additives mixed into the oil that make it even more effective? These additives are powerful chemicals designed to improve engine performance, protect parts from wear, and keep everything running clean. 

In this article, we’ll dive into the science of oil additives, how they work, and why they are so important for your engine’s health and efficiency. Whether you’re looking to boost engine performance or extend its lifespan, understanding oil additives is the first step!

Types of Lubricant Additives 

Lubricant additives are special chemicals mixed into base oil to make it work better. They help oil-protect engines and machines by improving their performance, removing bad effects, or giving them new helpful features.

Additives are usually 0.1% to 30% of the total oil, depending on what the oil is used for. Making the right mix of additives is tricky and can be expensive. The mix of additives decides what the oil is for—like engine oil, gear oil, or turbine oil.

Each additive has a job to do. Some help the oil last longer (like antioxidants), while others protect metal parts (like anti-wear or anti-rust additives). Additives are also picked based on how well they mix with oil and other additives and how much they cost.

In short, additives make oils stronger, longer-lasting, and better at protecting machines.

Conventional Lubricant Additives 

One common type of oil additive is called an antioxidant.

When oil is exposed to air, the oxygen can slowly damage it. This happens all the time but gets worse when the oil gets really hot or dirty. The damage creates acid (which can cause rust) and sludge (thick stuff that clogs things up and makes oil too thick).

To stop this, antioxidants are added to the oil. These special chemicals protect the oil by getting used up instead of letting the oil get ruined. That’s why they’re also called oxidation inhibitors.

Almost every engine oil or grease has antioxidants in it to help the oil last longer and keep machines running smoothly.

Rust and Corrosion Inhibitors

These additives help protect metal parts inside engines or machines. They stop rust and corrosion by blocking moisture and harmful acids from touching the metal.

Some are made to protect specific types of metal so that oils may have more than one kind. Almost every oil and grease you see has these in them. There’s also a special kind called metal deactivators, which work like corrosion fighters, too.

Viscosity Index Improvers 

These additives help oil stay the right thickness, even when temperatures change.

Oil usually gets thinner when it’s hot and thicker when it’s cold, but that’s not always good for machines. So, viscosity index improvers (VI improvers) are added to keep oil from thinning too much when it heats up.

This is super helpful in engine oils like 5W-30 or 15W-40. VI improvers also help the oil flow better when it’s cold, which protects engines and helps save fuel.

Imagine a VI improver like a spring or an octopus.

• When it’s cold, it stays small and doesn’t change the oil much.
• When it gets hot, it stretches out, making the oil thicker so it keeps protecting the engine.

But VI improvers have downsides, too. Because they are big molecules, some machine parts (like gears) can break them apart. This can make the oil lose its thickness.

Sometimes the oil temporarily gets thinner when it’s under pressure, like inside moving parts, but it goes back to normal afterward. This can actually help reduce how much fuel the machine uses.

There are many types of VI improvers. The better-quality ones last longer and don’t break as easily as the cheaper ones.

Anti-Wear (AW) Additives

Anti-wear additives are special ingredients in oil that protect metal parts inside machines. When parts rub against each other, they can get damaged. These additives help stop that damage.

They stick to metal surfaces and create a protective layer when things get really hot or when metal parts start to touch each other too much.

When machines are working hard and get hot, these additives form a thin film that keeps the metal from wearing down. They also help stop the oil from going bad and protect metal parts from harmful acids.

But here’s the thing:

These additives don’t last forever. They get “used up” as they do their job. When that happens, the metal parts can start to wear out faster.

One of the most common anti-wear additives is called ZDDP (zinc dialkyl dithiophosphate — yeah, that’s a mouthful!). It works great in both engines and hydraulic systems, depending on the type.

ZDDP also helps with oxidation and corrosion, which means it keeps oil fresh and metal safe. There are other similar chemicals, too, like TCP, that help protect your engine or machine.

Extreme Pressure (EP) Additives

EP additives are like super-protectors for machines that work under really heavy pressure. When two metal parts inside a machine press hard against each other, they can get so hot that they stick together or even weld. That isn’t good! EP additives jump into action when things get really hot and heavy. They create a protective layer on the metal so the parts don’t get stuck or damaged.

These additives are mostly used in gear oils, which is why gear oil sometimes has that strong, stinky smell — it’s the sulfur in the EP additives!

EP additives are made from things like sulfur, phosphorus, and sometimes boron. But here’s a warning: they can damage yellow metals like copper and brass, especially when things get hot. So, you shouldn’t use them in machines with copper parts (like worm gears).

Both anti-wear (AW) and extreme pressure (EP) additives do a similar job — they protect metal surfaces when the oil can’t fully separate the parts. As long as oil is flowing well and creating a smooth layer between metal parts, these additives hang out and wait.

But when that smooth oil layer breaks down under heat or pressure, AW and EP additives jump in to protect the metal parts from damage.

Detergents

Detergents in engine oil do two important jobs. First, they help keep the engine parts clean by stopping dirt and build-up from sticking to the hot metal. Second, they fight against harmful acids that form in the oil. These detergents are usually made from chemicals like calcium and magnesium and are basic (not acidic).

The strength of how much acid the oil can fight is called the base number (BN). In the past, some detergents were made from barium, but those are hardly used now.

Because these detergents are made from metal, they can leave behind ash when the oil burns, which can cause problems in engines that run very hot. That’s why some engine makers now recommend using low-ash oils. Detergents are often used along with something called dispersants to work better together.

Dispersants

Dispersants are also used in engine oil and often work together with detergents. Their main job is to keep tiny dirt particles, like soot from diesel engines, spread out evenly in the oil. This keeps the dirt from clumping together and causing damage inside the engine.

Dispersants help carry the dirt out when the oil is changed. They are usually made from non-metal materials, so they don’t make ash and are hard to find in regular oil tests.

When detergents and dispersants work together, they keep the engine clean and safe by stopping acid and holding onto dirt. But over time, they get used up. When that happens, it’s time for an oil change.

Also Read: 

• What is the Role of Anti-Wear Additives In Lubricants
• How Often Should Anti-Wear Additives Be Applied?

What Do Oil Additives Do for Your Engine?

Engine oil (also called motor oil) has two big jobs:

• It helps the parts inside your engine move smoothly by reducing friction (rubbing).
• It protects metal parts from rust (which happens when metal gets damaged by things like water or air).

But engine oil can’t do all this on its own — it needs help from extra ingredients called additives. One of the most important additives is something called a viscosity index improver, or VII for short.

What is Viscosity, and Why Does It Matter?

Viscosity is a fancy word that means how thick or thin the oil is. If oil is too thick, it moves slowly and can clog things up. If it’s too thin, it moves too fast and doesn’t stick to the engine parts long enough to protect them.

The tricky part is that oil changes thickness with temperature:

• When it’s cold, the oil gets thicker.
• When it’s hot, the oil gets thinner.

That means your oil might not work well on a cold winter morning or during a hot summer drive — unless it has VIIs. These help the oil stay the right thickness, whether the engine is cold or hot.

Other Common Additives

Besides VIIs, engine oils usually include:

• Rust inhibitors to stop parts from rusting.
• Detergents and dispersants to clean out sludge (thick, dirty build-up) inside the engine.
• Zinc, which helps protect engine parts from wear.

Most of these additives are already mixed into the oil when you buy it, so you don’t have to add them yourself.

Boost Your Engine with Oil Additives

Oil additives are special chemicals added to engine oil to help it work better. They reduce friction, protect parts from wear, clean the engine, and help the oil flow smoothly.

What Do Oil Additives Do?

• Improve Engine Performance: They reduce friction and keep the engine clean.
• Extend Engine Life: Additives protect parts from wear and rust.
• Save Fuel: By making the engine work better, they help save gas.
• Help the Environment: Some additives clean the engine, reducing pollution.

Oil additives make your engine run smoother, last longer, and use less fuel. Most good oils already have these additives, so your engine gets all these benefits without extra work!

Final Thoughts

Oil additives play a crucial role in keeping your engine running smoothly and efficiently. By improving lubrication, protecting against wear and rust, and keeping the engine clean, these additives help extend your engine’s life, save fuel, and even reduce harmful emissions. 

While many high-quality oils already contain the right additives, understanding how they work can help you make informed choices. So, next time you’re picking engine oil, remember that the right mix of additives is key to keeping your engine in top shape!

FAQs

Q1: Is it necessary to use a motorcycle engine oil additive?

No, you usually don’t need extra additives if you’re using good-quality motorcycle oil and changing it on time. Most oils already have the right additives.

Q2: Can you use oil additives in a motorcycle?

Yes, oil additives can be used in motorcycles. They help reduce engine wear by up to 43%, improve fuel economy by up to 5%, and restore lost compression.