Semi-Synthetic (aka Conventional) vs Synthetic Oil: Their Differences Explained

Published on

May 29, 2024

Mechanic pouring oil as part of oil change and understanding the differences between conventional vs synthetic oil

All drivers should know how important routine oil changes are to the health of their engines and the longevity of their vehicles, but how well do you know the product that's being put into your vehicle?

Contrary to what many drivers may think, there's more than just one type of motor oil. Two of the most popular blends are conventional and synthetic motor oil. In this post, we'll explain the key differences between conventional, or also known as semi-synthetic, and synthetic motor oil and let you know what blend is best for your vehicle.

Read on to learn more about conventional vs synthetic oil or contact your local GreatWater-affiliated shop today for more information.

What is Conventional Oil?

Conventional motor oil is mineral oil captured through refining crude oil. While this crude oil is distilled and processed before it's bottled and sold, conventional oil is largely unchanged from the time it exits the refinery and is put into your engine. As the "conventional" name implies, there's nothing special about this type of oil. But in many cases, it does the job well.

What is Synthetic Oil?

Unlike conventional motor oil, synthetic oil is engineered and optimized in a lab. Because it's purposefully engineered for vehicle engines, synthetic oil offers various performance advantages over conventional blends. We'll get into more of that in the next section.

It's also worth noting that there are different types of synthetic blends. For instance, there are full synthetic blends of motor oil and semi-synthetic mixes as well.

Key Differences: Conventional Oil vs. Synthetic Oil

Now that we've outlined the basics of semi-synthetic/conventional and synthetic oil, let's discuss some of the key differences of each type of blend. Here's a closer look at the advantages and disadvantages of both semi-synthetic/conventional and synthetic motor oil.

Advantages of Semi-Synthetic/Conventional Oil

After reading the first section, you may have immediately jumped to the conclusion that synthetic oil is the better choice for your vehicle. But there are plenty of reasons why drivers still elect for semi-synthetic/conventional motor oil. These reasons include:

  • It's cheaper and easier to find: Synthetic oil can be twice as expensive as conventional motor oil. It's also the more widely available motor oil.
  • It's good for old engines: Have more than 75,000 miles on your vehicle's odometer? Most auto manufacturers suggest using semi-synthetic/conventional motor oil. Why? Since conventional oil flows a bit slower than synthetic blends, it can ensure it's better lubricating aging engine parts.
  • You probably don't need synthetic oil: Synthetic oil is ideal for high-performance cars or drivers who routinely operate their vehicles in extreme temperatures. For the majority of vehicles, semi-synthetic/conventional oil works just fine.

Disadvantages of Semi-Synthetic/Conventional Oil

The main disadvantage of semi-synthetic/conventional oil is that it doesn't perform as well as synthetic oil. What's more, synthetic oils can be created to cater to any specific engine or application.

Advantages of Synthetic Oil

Some of the key benefits of synthetic oil include:

  • It protects better at extreme temperatures: In a heatwave or a cold snap? Synthetic oil is still going to offer premium engine protection. In cold temperatures, oil can take a while to flow through the engine, but synthetic oil is designed to flow quickly in cold temperatures. Conversely, synthetic oil is better designed to resist breaking down or evaporating in high temperatures.
  • It protects important components: Synthetic oil blends are ideal for performance vehicles, notably those with turbocharger parts and components where oil can become very hot.
  • It keeps the engine cleaner and offers better wear protection: Synthetic oil is crafted with fewer impurities compared to conventional blends, which helps promote a cleaner running engine. Additionally, the better-flowing nature of synthetic oil helps prevent engine wear and can better safeguard components.

Disadvantages of Synthetic Oil

Perhaps the biggest disadvantage to synthetic oil is the price. Many blends can cost twice as much as their conventional counterparts. And considering that many vehicles will run fine on semi-synthetic/conventional motor oil, the additional cost can be a major prohibiting factor.

Which is Right for Your Vehicle?

So what's right for your vehicle - semi-synthetic or synthetic oil? It depends on your specific vehicle, the climate that you're driving in, and your personal preference.

Some situations where you want to consider a synthetic blend of motor oil may include:

  • You're driving a high-performance vehicle with turbocharged components.
  • You regularly drive in either extreme cold or extreme heat.
  • You have the budget to buy the better-performing oil and want to ensure your vehicle is getting the best.

As we said earlier, in most cases, conventional oil will suit a vehicle just fine. And in older vehicles, the slower-flowing motor oil is actually preferred by many mechanics to ensure it's fully penetrating aging engine parts.

If you're not sure what type of motor oil would be best for your car, make sure you ask a trusted mechanic what they'd recommend. At GreatWater, we're always happy to explain the pros and cons when it comes to conventional vs synthetic oil to help empower our customers to make the right decision for their vehicles. And we're also happy to make a recommendation.

Contact GreatWater Today

For more information on the key advantages and disadvantages of conventional and synthetic motor oil, contact your nearest GreatWater-affiliated location today.

As a full-service auto repair and maintenance center, our technicians will perform any service at any one of our locations - from a routine oil change to flushing transmission fluid. And in addition to the industry-leading service that you can expect any time you bring your vehicle to one of our neighborhood shops, you can also ensure first-class customer care. It's part of the value proposition of doing business with a shop in the GreatWater network, we'll treat you just like a neighbor.

For more information and to schedule an appointment, contact us today.