Skip to Content

What Is An Engine Oil Additive and Is It Worth It?

  • Jan 11,2021
What Is An Engine Oil Additive and Is It Worth It? What Is An Engine Oil Additive and Is It Worth It?

person standing in front of car engine cleaning oil dipstick with red ragYou stop by the auto parts store for new seat covers and floor mats. You stroll down an aisle with shelves and shelves of engine oil additives that promise to deliver better gas mileage, a cleaner engine, and more horsepower. Is your vehicle missing out? Is extra engine oil additive worth it?

Learn more about oil additives before you pick one off the shelf and pour it into your vehicle's most important component — the engine.

What Is An Engine Oil Additive?

It’s helpful to know the primary purpose of motor oil itself before you can understand the function of an engine oil additive. Motor oil's function is to lubricate your engine and reduce friction between its many moving parts. Oil also plays a critical role in protecting against corrosion, helping remove contaminants, preventing sludge build-up, and keeping the engine cool.

Your everyday engine oil is already a combination of base oils and additives. "The base oils constitute 70-90 percent of the total and are created from natural gas or crude oil, while additives round out the remaining 10-30 percent and can be a variety of things," notes Pennzoil.

There are different additives for different applications. Additives can include detergents, anti-wear additives, friction modifiers, antioxidants, corrosion inhibitors, viscosity index improvers, and more. Millions of dollars and hours go into creating and testing oil formulations so that they're just right.

Most of the brightly colored bottles you see at the auto parts store are aftermarket or supplemental engine oil additives. Some claim to extend the oil’s life and others say they reduce engine smoking. However, there’s mixed research as to whether they do what they claim.

What Engine Oil Additives Do To the Engine

The majority of motor oils contain around 15% of additives. Without additives, the oil is essentially unable to perform its critical functions. Wear, oxidation, and decomposition can cause the oil to degrade over time.

Engine oil can lose its additives the older the oil gets. Without the proper levels of these additives, you run the chance of increased wear and tear on your engine, potentially resulting in rust, corrosion, oil sludge, decreased fuel economy, breakdowns, overheating, and expensive engine damage.

That's one reason a driver might consider an aftermarket or supplemental engine oil additive between oil changes — they want to reinvigorate their oil as quickly as possible. The value of an additive, though, would be whether it contains the additives that have been depleted and if it offsets any of the other existing additives remaining in the oil. Many different types of oil additives work by attaching their molecules to an internal engine component. Too much of one additive may limit a second necessary additive from being able to do its job.

Are Engine Oil Additives Any Good?

The question of using aftermarket engine oil additives has been the subject of controversy for years, and the answer isn't a simple "yes" or "no." You may assume that since standard motor oil already contains additives, any additional additives aren't necessary. But it's not always that black and white. You'll want to do your research, consult your vehicle manufacturer, particularly if your car is still under warranty, and make the decision for yourself.

"When it comes to supplemental additives, I always say it's a consumer's choice," says Shell Lubricants Global OEM technical manager. "Petroleum chemists and automotive engineers are really smart people who know what is and is not needed,” he says. “Oil already comes with additives in it to do certain things, so the consumer should piggyback off that knowledge and lean towards oil additives that are carefully formulated into the oil by the oil manufacturer to provide extra improvement in those areas.”

There are two factors to consider when deciding if aftermarket oil additives are a good idea for your vehicle, including:

  • Warranty: Most importantly — double-check your manufacturer's warranty. “Adding additional [aftermarket] additives to an engine oil could unbalance the additive system, resulting in detrimental side effects and potentially invalidating the engine manufacturer’s warranty,” reports the OEM technical liaison for Petro-Canada Lubricants.
  • Mileage and Vehicle Age: The more miles you have on your engine, the more likely it is that your engine is operating at less-than-maximum performance, making it more vulnerable to possible damage. The addition of certain oil additives carefully balanced into a fully-formulated high mileage engine oil has the potential to reduce stress and wear on your high-mileage engine and help restore performance. Consistently using a quality high-mileage oil can help.

Start with an Oil Change

When it comes to what's best for your engine, adding aftermarket engine oil additives may be a bit of a gray area. Ultimately, getting regular oil changes with high-quality oil that meets your vehicle manufacturer’s recommendation can be more beneficial for your vehicle’s long-term performance and comply with your vehicle’s warranty.

At Firestone Complete Auto Care, we’ll always prioritize what’s best for you and your car! That’s why we use high-quality motor oil brands like Pennzoil and always refer to your manufacturer's suggested maintenance recommendations to decide which type of high-quality oil to use on your engine.

Schedule your next oil change service appointment at your local Firestone Complete Auto Care, and talk to our expert technicians about the benefits of a high-quality Pennzoil oil change.

Up Next

Find Store

Find a Different Location

Stores Near You

Do you want to change your Preferred Store?