Oil changes are important car maintenance procedures to ensure your car is working smoothly, road-worthy, and is safe to drive. Changing your vehicle’s oil can reduce excess dirt build-up in the engine. It prevents sludge-related engine trouble that can affect the engine’s efficiency and eventually cause it to break down.

The American Automobile Association suggests changing your engine oil every 5,000 to 7,500 miles. However, it would depend on your engine and the oil you are using. But if your engine oil is oxidizing, it may affect the frequency of changes.

What is oxidation, and how does it impact engine oil changes? Keep reading to find out.

What Is Engine Oil Oxidation?

When a lubricant’s oil base oxidizes, the molecules, which are often hydrocarbons, interact with oxygen in the form of foam or entrained air. As this process takes place, the molecules are transformed into proponents that hinder the lubricant’s performance. Once oxidation begins, you cannot reverse it. 

Why Is Oil Oxidation a Cause for Concern?

Oxidation is one of the leading causes of lubricant degradation. The oxidation process occurs when lubricants are subjected to common conditions, such as heat, exposure to oxygen, and friction. 

While the main concern for oxidation is its effect on engine efficiency, other issues can stem from it. These include increased oil viscosity, sludge accumulation, amplified varnish potential, and corrosion. Furthermore, engine failure is possible if you don’t address the problem promptly and properly. 

How Does Oxidation Negatively Affect Cars?

Oxidation gives rise to numerous complications. Most issues begin with the base oil breaking down as additive depletion occurs. 

The viscosity and acidity of the oil will often increase, and rust and corrosion will take effect. Moisture and reactive metals also contribute to the rate of oxidation.

How Does Oxidation Impact the Frequency of Oil Changes?

When you have a better understanding of oxidation, you can see how it can affect the degradation rate of the lubricant. It directly impacts the frequency at which the oil is needed to be changed out. 

Antioxidant depletion and lubricant type heavily influences the frequency of the change. If the additives deplete faster and the oxidation rate increases, a more frequent change of engine oil is needed. Similarly, if the lubricant used in the car is a synthetic blend, the possibility of oxidation occurring is higher and would require more frequent changes.

How Do You Check Oxidation in Cars?

The engine oil is checked for signs of oxidation during preventive maintenance checks and inspections. During this time, auto mechanics will use a clean sight glass with a flashlight. 

They will check if the engine oil is clear and bright—or at least the color that it should be out of the bottle. Foul-smelling, darker-than-normal lubricants are considered oxidized.

How to Fight Off Oxidation?

Paying close attention to the oil you use is one of the best ways to fend-off oxidation. Fully synthetic lubricants are considered the most resistant type of oil available in the market. Base oils with higher viscosity indexes can also effectively resist oxidation breakdown. 

Additionally, ensuring that the lubricants you use have antioxidant additive packages enables you to combat oxidation. Lastly, make sure that the fittings in your circulating lubrication system are properly secured and that no air will enter it.


Being knowledgeable about oil changes is important for your vehicle and you as a driver. With the information provided above, you should have a good grasp of what engine oil oxidation is, why you should avoid it, and how it affects your vehicle. Take time to keep a lookout for the early signs of engine oil oxidation. Should you ever experience engine oil oxidation, contact your local auto mechanic as soon as possible to avoid larger problems.

Do you need an oil change in Hoover, AL? Hoover Automotive is at your service! We are a BBB-accredited auto repair shop offering a wide range of top-notch services. From auto repairs to car maintenance services, rest assured that we have your back. Contact us today to learn more about how we can help you!

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