Synthetic Blend vs Full Synthetic vs Conventional Oil

by Synthetic Oil | Last Updated: December 4, 2022

When you are preparing to change engine oil for the first time, you may have many questions. For instance, you may wonder, “How do I know which oil to use?” Does one kind of oil suit your vehicle better than others? It is essential to understand the differences between synthetic blend vs full synthetic vs conventional oil if you want to keep the engine running without any issues.

**Note** – A quick hello to anyone reading this, I’m Alastair and this is my site Synthetic I started this site to help people with their oil questions, and hopefully what you’re about to read will help answer your questions. This page may include affiliate links to the likes of Amazon, which if you make a purchase I qualify to earn a (typically small) commission. Don’t worry as this won’t cost you anything, the likes of Amazon pay any commissions. Thank you in advance for your support as this helps bring you more (hopefully) helpful content.

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What is Conventional Oil?

Conventional oil has been used in engines for many years. It is made from either crude oil or petroleum. Being that petroleum—a form of fossil fuel—is abundant, it is often used in jet fuel, diesel, and gasoline.

However, does your car need conventional oil? Probably not. Unless, of course, you are driving a car that was made before the 1990s. After the 90s, the industry-standard shifted. Engines started to become similar to the more fuel-efficient models we have today.

Conventional oil is thicker than synthetic oil, meaning that it flows much slower through the engine. In modern engines, conventional oils do not protect as well against wear and tear as well as synthetic blends and full synthetics.

This video provides a detailed explanation of conventional vs synthetic oil:

What is a Synthetic Blend?

Also known as a semi-synthetic, this kind of oil is a mix between a synthetic formula and conventional oil. A blend contains 30% synthetic oil or less, but it still has far more protective power than regular conventional oil. This kind of oil is also less vulnerable to evaporation.

The main advantage of a synthetic blend is its affordability. For less of an investment, you get nearly the same level of protection as you would a full synthetic.

What is Full Synthetic Oil?

There are many forms of synthetic motor oil (because there are no regulations on the formula). As such, synthetics can be a combination of petroleum-based with modifiers or additives to enhance it. Synthetic engine oil has many benefits, including a lower viscosity than conventional oil. This reduces the amount of friction, leading to better fuel economy and enhanced performance.

Synthetics, due to their composition, also contribute less sludge and are excellent at dissipating the heat from the internal combustion engine. They work well at both ends of the temperature range because synthetics do not suffer from the same variability as conventional oil.

Lastly, fully synthetic oils stay stable for longer, which has contributed to longer periods of time between oil changes. To compare, conventional oil needs to be changed once every 3 months or 3,000 miles. Meanwhile, synthetic oil can be changed every 5,000 to 10,000 miles, depending on the make, model, and mileage of your vehicle.

What Are The Differences Between Synthetic Blend and Full Synthetic?

There are a couple of differences between synthetic blend vs full synthetic that you should know about. First off, fully synthetic motor oil does not contain any natural oil, while synthetic blends do. A full synthetic is made in laboratories. Because of that, fully synthetic motor oil often costs more than a synthetic blend.

Furthermore, synthetic blends do not last as long as full synthetic. While blends tend to have a longer oil change interval than conventional oil, it is still recommended to change your oil even 6,000 miles. Full synthetics, as mentioned earlier, have a range between 5,000 and 10,000 miles. That said, some makes of vehicles, such as Honda or Toyota, have been known to last 15,000 miles on full synthetic oil.

Both forms are excellent at preventing sludge buildup in the engine, though a full synthetic oil will do a better job of protecting against friction and corrosion. When it comes to heavier use, including construction work, it is recommended that SUVs and pickup trucks use a synthetic blend instead of a fully synthetic one.

Which Type of Oil is Best For Your Car?

Now considering the different types of engine oil and their pros and cons, you may be wondering how to pick the right oil for you.

This video provides some advice:

Generally speaking, there is only one time you would ever need to use conventional oil: if you own a pre-90s vehicle. That being said, full synthetic oil is completely safe to use in a vintage engine. You may even preserve an original motor for far longer by using a full synthetic instead of continuing on with conventional oil.

Modern cars can use either a synthetic blend or full synthetic without much difference. If you are worried about the cost, you may find that a synthetic blend is more budget-friendly. Optionally, you can choose to rotate between full and semi-synthetic oil, since they work more or less the same.

Keep in mind that each car, truck, or SUV is going to come with a manufacturer’s recommendations in the owner’s manual. Where one requires a 5W-30 motor oil, yours may have a recommendation for 0W-30 or 10W-40. For the best performance and fuel economy, follow the guidelines. When your car gets beyond 75,000 miles on the odometer, consider switching to a high mileage full synthetic oil.

Choose Your Oil Wisely

Now that you know the differences between conventional oil vs synthetic blend vs full synthetic, which one are you going to choose? For most cars, a synthetic blend or full synthetic is ideal. Weigh your options alongside the manufacturer’s recommendations before deciding. You want to choose the motor oil that supports the best performance throughout the year.