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Synthetic Blend vs Full Synthetic Oil: Which One is Better?

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Synthetic blend vs full synthetic oil — what’s the right choice for your engine

While both come from the same base crude oil as conventional oil, they differ significantly in composition, pricing, and performance.

So, which is more favorable to your engine?
And are they better than conventional oil?

We’ll highlight the major differences between the two oils and examine their benefits, helping you determine the better choice. We’ll also discuss factors to consider when selecting the right oil for your engine.

This Article Contains:

Let’s get right into it!

Synthetic Blend vs Full Synthetic Oil: What’s the Difference?

Fully synthetic oil and synthetic blend oil are both types of motor oil that provide lubrication and protection for various engine parts. These oils help prevent problems like engine wear, sludge formation, corrosion, and overheating. 

Despite sharing some common ingredients, synthetic blend oil (semi-synthetic oil) and fully synthetic oil are different. 

Here’s how: 

1. Composition

Fully synthetic oil and synthetic blend oil differ in their base oil formulations and additive packages, each designed to meet specific engine performance needs.

A. Full Synthetic Oil

Fully synthetic oil is chemically created in the laboratory consisting of highly refined crude oil as the base oil. This base oil is obtained by modifying the base structure of hydrocarbon atoms, thus preserving the best molecules in the process for superior performance.

Besides the chemically engineered base oil, fully synthetic motor oil incorporates additives to create the final product.

B. Synthetic Blend Oil

Synthetic blend oil combines traditional mineral oil and synthetic motor oil as its base. Additional chemical additives and modifiers are then incorporated to enhance performance, improve viscosity, and provide better engine protection compared to conventional oil.

The ratio of conventional motor oil and fully synthetic oils in a synthetic blend can vary from brand to brand. Therefore, some semi-synthetic oil blends might perform better than others.

2. Pricing

Fully synthetic oil is generally more expensive than synthetic blend oil. Drivers need to consider this factor when choosing the right engine oil. 

A. Full Synthetic Oil

Due to the complex manufacturing process of full synthetic oil, it costs 30% more than any synthetic blend oil. It can also be expensive to maintain, especially considering how much more you pay per quart of motor oil.

B. Synthetic Blend Oil

Since synthetic blend oil is much easier to obtain, it tends to be cheaper than the full synthetic option. Consequently, it’s more economical and sustainable to maintain.

3. Oil Change Intervals

The length of your oil change interval is determined by the engine oil you use for your car. While conventional motor oil has a very short oil change interval, fully synthetic oil change and synthetic blend oil change intervals vary in the following ways:

A. Full Synthetic Oil

Due to its highly refined nature and the presence of synthetic additives, fully synthetic oil performs far better than any other motor oil.

A fully synthetic oil change interval can go about 5,000 miles on the lower end. Sometimes, it can allow a Toyota, Ford, or other vehicle to go anywhere from 10,000 to 15,000 miles before needing a change.

B. Synthetic Blend Oil

A synthetic blend oil change can achieve an average of 5,000-7,500 miles. It performs far better than mineral oil due to its balanced ratio of conventional base oils to synthetic base oil. However, it doesn’t outperform fully synthetic engine oil. 

Both synthetic blend motor oil and fully synthetic oil have their advantages. Both consistently outperform traditional oil in terms of performance and protection. 

But which one is better than the other? 
Let’s understand by comparing the pros of using each oil type. 

Benefits of Synthetic Blend vs Full Synthetic Oil

In general, synthetic blend oil and fully synthetic oil help: 

Synthetic blend motor oil and fully synthetic oil also have various other uses. Due to their unique properties, they are better suited for certain applications compared to regular oil. 

Here are the specific perks of each oil type:

A. Benefits of Full Synthetic Oil

Unlike conventional motor oil, fully synthetic engine oil is highly refined, contains fewer impurities, and is formulated with higher-performing chemical additives. Even when compared to synthetic blend oil, it has many advantages that often make it a favorable choice. 

These include: 

B. Benefits of Synthetic Blend Oil

A synthetic oil blend achieves a middle ground between mineral oil and fully synthetic engine oil in terms of performance and oil change interval.

It offers the following benefits:

Considering these benefits, how do you decide which engine oil is right for you? 
Let’s find out.

How to Pick the Right Motor Oil for Your Car

Generally, both fully synthetic oil and synthetic blend oil outperform traditional oil (conventional oil). But when choosing between the two, you must consider your engine age, driving habits, budget, and car manual specifications.

Let’s break down each factor: 

1. Budget

If it’s an affordable choice for you, fully synthetic oil will do wonders for your car engine. However, synthetic blend oil is also a pretty good alternative to regular oil. 

Generally, an automotive technician rotates between a semi-synthetic and fully synthetic oil change to cut down on costs while still achieving high performance. You can also initially start using a synthetic oil blend before completely switching to fully synthetic oil.

2. Engine Age

It’s important to look at your engine’s age and condition before selecting the oil type. For example, older cars typically run better on high-mileage or conventional mineral oil.

3. Driving and Weather Conditions

If you live in a cold climate, full synthetic oil is ideal. It’s engineered to maintain its viscosity and flow properties more consistently across extreme temperatures, providing better performance than synthetic blends.

4. Manufacturer Recommendations

Most importantly, let your car manual decide the type of oil your engine needs. Also, keep track of the oil viscosity grade levels these oils offer, and choose accordingly.

For example, viscosity grade 5W-30 is one of the most commonly recommended engine oils for everyday driving and extended road trips. It performs well in a wide range of temperatures and conditions.

Under this viscosity grade:

NOTE: The lower the first number, the better the oil performs in cold starts, and the higher the second number, the better it protects engine parts at high temperatures.

Got more questions about engine oil?
Keep reading. 

4 Important FAQs About Engine Oil

Here are the answers to some common queries about engine oil:

1. What are the Different Engine Oil Viscosity Grades?

Engine oils are classified based on a rating system developed by the Society of Automotive Engineers (SAE). It categorizes oil based on its viscosity, i.e., its resistance to flow. 

Thin fluids like water have low viscosity, while thicker fluids like oil have high viscosity. Motor oil viscosity changes with temperature, becoming thinner when heated and thicker when cooled.

Engine oils fall into two main categories based on viscosity grades:

2. What Important Symbols Should Your Engine Oil Have?

The oil brand you choose should have the symbols of API/ILSAC “Starburst” (on the front label) and API “Donut” (on the back label). 

The Starburst logo indicates that the particular oil meets ILSAC (International Lubricant Specification Advisory Committee) standards for gasoline engines. The Donut sign shows the oil’s API (American Petroleum Institute) service rating, SAE viscosity, and resource-conserving properties. 

These symbols ensure the oil meets superior performance standards. Pennzoil Platinum, Valvoline, and Castrol are some brands with these certifications.

3. What Happens if You Put the Wrong Oil in Your Engine?

Adding an oil of unsuitable viscosity can damage your car’s critical engine parts, reducing their reliability and lifespan. Your car’s fuel efficiency will also take a hit.

If you accidentally add a high-viscosity oil instead of the recommended thinner oil to your car, drain it immediately and get an oil change

Remember, using a thicker or thinner oil than the one recommended can also void your car’s warranty.

4. Can You Mix Engine Oils of Different Viscosities?

Ideally, you shouldn’t mix oils of different viscosity ratings. Mixing can alter the engine oil’s ability to maintain its structure across different temperatures, leading to ineffective lubrication.

Additionally, different oils contain different viscosity modifiers and corrosion inhibitors that may be incompatible with each other.

Keep Your Engine in Top Shape with the Right Oil

Both fully synthetic oil and synthetic oil blends offer several benefits as compared to regular oil. However, you need to check your owner’s manual for engine oil specifications. 

Regardless of the type of oil you choose, regular oil changes are essential to keep your engine running smoothly and prevent serious issues. 

If you need any help with your oil change, contact the seasoned mechanics at AutoNation Mobile Service

Our mobile mechanics will come to you, change the oil, make other necessary auto repairs, and get you back on the road quickly. We’re available seven days a week and offer upfront pricing, so you’ll know what to expect.

Contact us to resolve your engine oil woes right away!