When choosing the right motor oil, understanding the benefits of synthetic oil vs. conventional oil vs. synthetic blend is essential. Each type offers unique advantages tailored to different driving habits and engine needs.
Regular oil changes also play a vital role by removing contaminants that build up over time, ensuring your engine performs better and lasts longer.
Selecting the right motor oil is one of the most important decisions you can make for your engine’s health and performance. Let’s dive into the key differences and benefits of synthetic oil, conventional oil, and synthetic blends to help you make an informed decision.
Motor oils are designed for a variety of applications, from passenger cars to high-performance vehicles, and even specialized oils for race cars. Several factors, such as driving conditions and vehicle type, determine whether conventional, full synthetic, or a synthetic blend is the best choice for your engine.
What Does Oil Do in A Car?
Engine oil is the lifeblood of your car, playing a crucial role in keeping your engine running smoothly. But why should you care about understanding oil types? Choosing the right oil can improve engine performance, extend its life, and even save you money over time.
Whether you’re commuting, towing, or pushing your vehicle to its limits, understanding oil basics ensures your car stays in peak condition.
A vehicle engine operates at low temperatures. But it can operate at very high temperatures, sometimes extreme. Besides lubrication, engine oil has many other important functions:
- Reduces engine wear
- Keeps engine parts cool
- Prevents deposits from forming on internal engine parts
- Suspends and removes contaminants in the oil
- Protects the engine across a wide range of temperatures
- Provides optimal fuel efficiency
- Conditions seals
When comparing synthetic vs conventional oil, they have four primary functions. Those functions are lubricated, protect, cool, and clean.
What is Conventional Oil?
Conventional motor oil is derived from crude oil and contains impurities. There are no additives added to the oil, and it has irregularities at the molecular level. Conventional oil will accomplish the basic task of lubricating your engine by coating the vital parts of your engine that run at high speeds and providing a barrier against engine wear.
Conventional motor oil will break down more quickly than synthetic motor oil and require more frequent oil changes. As conventional oil ages, it begins to leave carbon deposits in your engine, forming “engine sludge” with continued use. This engine sludge can reduce the life of your engine.
In extremely hot or cold conditions, conventional motor oil can be susceptible to the elements. In high heat, conventional oil can start to boil off, causing a loss of lubrication to engine parts running at high speeds.
In very cold conditions, conventional oil can become thick and less fluid, meaning it may not reach all of the vital engine parts quickly enough as the engine warms up, which can lead to damage.
Pros of Conventional Oil
Conventional oil has been used since the invention of the first car, so it’s withstood the test of time thanks to its many pros:
- Conventional oil is more affordable. Because it is less refined and processed than synthetic oil, it is cheaper to produce and thus cheaper for consumers looking to limit their ownership costs.
- Conventional oil is more readily available. Conventional oil is available at every repair shop. You won’t need to shop around to find it.
- Conventional oil is better for older engines. Due to its higher viscosity (an oil’s thickness and ability to flow), conventional oil flows more slowly through your engine, ensuring every part is lubricated. Older engines require more lubrication to keep things running smoothly and resist breakdown, so many mechanics recommend conventional oil for cars over 75,000 miles.
- Most manufacturers recommend conventional oil for most cars and driving conditions. Chances are, the dealership filled your car with conventional oil when you purchased it.
Cons of Conventional Oil
The number of cons outweighs the advantages of conventional oils, making them more undesirable than desirable. Below are a few to consider.
- Conventional oil may slightly lower your gas mileage. Because it lacks a consistent molecular size, conventional oil is thicker and less smooth than synthetic oil. As a result, your engine may have to work harder, resulting in lower gas mileage.
- Conventional oil is more susceptible to extreme temperatures. In the cold, it thickens, which means it takes longer to circulate. (This is why experts recommend warming up your engine before driving in the winter.) Conventional oil can evaporate and degrade in the heat, requiring more frequent oil changes to protect your engine.
- Conventional oil doesn’t last as long as synthetic oil. As an organic product, conventional oil breaks down faster than synthetic oil. Experts recommend changing your conventional oil every 5,000 to 7,000 miles. Since you will need more oil changes over time, this may offset the cost savings of a conventional oil change.
- Conventional oil is less environmentally friendly. Since conventional oil can leach contaminants from the air, deposits can build up in your engine. These deposits can cause your engine to work harder and produce more emissions. Used oil is also toxic waste, so the increased frequency of oil changes produces more toxic waste.
What is Synthetic Blend Oil?
Synthetic Blend oil is kind of like a hybrid of conventional oil and full synthetic oil. The two oils are basically mixed together so that you’ll have oil that is a little bit better than conventional oil. Most blend oils will have a synthetic oil content varying from 10% to as much as 25%.
The idea behind the creation of such motor oils is all about offering some of the inherent benefits of synthetic oil, while still sticking to conventional motor oil as the prime component.
While these motor oils offer marginally better performance under extreme temperature conditions, compared to conventional oils, they do not provide the full import of the advantages that synthetic oils offer.
Pros of Synthetic Blend Oil
There are many benefits to choosing synthetic blends over conventional oil. Here are a couple of reasons to consider it.
- Lower cost than synthetic: You can get many of the same benefits as synthetic oil, but for a slightly lower price.
- Increased fuel economy: With more lubrication for the engine, it doesn’t have to work as hard, so you should see better fuel economy.
- Reduced emissions: The better the fuel economy is, the lower the emissions are.
- Special detergents/additives: Companies put in special additives and detergents to boost the engine’s well-being.
- Longer service life: You don’t need to change the oil as often as with conventional oil.
Cons of Synthetic Blend Oil
There are some troubles with synthetic blends that are important to recognize. Here are the major complaints.
- Costs more than conventional: You have to spend more than you would for a conventional oil change.
- Formulas differ: Because there are no regulations, you could be paying for something greater than conventional, but the formula may not be too much different.
- Not as accessible: Not all shops use synthetic blends. In fact, there’s speculation that these could be removed as an option in the coming years due to a big push toward full synthetic.
What is Full Synthetic Oil?
Contains a mixture of additives that allow the oil to break down more slowly and provide greater lubrication for your engine. Synthetic oil offers better performance in extreme cold or extreme heat.
The synthetic oil flows and coats engine parts quicker in the cold of winter and breaks down more slowly in the extreme heat of the summer, and continues to protect your engine from wear.
The benefits of synthetic oil also include extending the life of your engine. At the molecular level, synthetic oil is uniform. Due to a refining and purification process, it will keep your engine cleaner and last longer, resulting in a clean-running engine for years to come.
Synthetic oil has also been shown to improve fuel economy and engine performance when compared to conventional oils.
Synthetic oil is continuing to see improvements in modern technology and chemistry. While the cost of synthetics is greater in the short term, the long-term effects of using synthetic oil over conventional oil will result in a car that will last longer and require less frequent oil changes.
Pros of Synthetic Oil
Synthetic oil has been around since the 1930s, but it wasn’t frequently used in cars until the 1980s. Proponents of synthetic oil claim the following benefits:
- Synthetic oil lasts longer. Synthetic oils are rated to last about twice as long as conventional oil, reducing the number of oil changes. While it varies based on brand, most synthetic oil manufacturers recommend you change synthetic oil between 10,000 and 15,000 miles or every six months or year.
- Synthetic oil keeps your engine cleaner for longer. Because synthetic oil is human-made, it contains fewer impurities than conventional oil. As a result, it resists the formation of deposits and sludge, improving your engine’s performance.
- Synthetic oil is better for turbochargers. To create lighter, more fuel-efficient cars, manufacturers are building vehicles with smaller engines and a turbocharger. The turbocharger compresses air through the cylinder, allowing for faster speeds and better performance, but turbochargers require more oil flow in excessive heat conditions. Synthetic oil flows faster and degrades less under heat conditions than conventional oil, so manufacturers often recommend synthetic oils for vehicles with turbochargers.
- Synthetic oil has better viscosity. Synthetic oil is more stable than conventional oil, so it has better viscosity. This allows it to flow quickly and smoothly in all temperatures and resist extreme heat, improving your engine’s performance.
- Synthetic oil may improve gas mileage and horsepower. Because synthetic oil flows so smoothly through the engine, it reduces friction. You may find your horsepower and gas mileage higher than if you used conventional oil.
- Synthetic oil performs better overall. Our Engine Oil Research study revealed that synthetic oil performs an average of 47 percent better compared to conventional oil in industry-standard tests. Most vehicles can use synthetic oil even though manufacturers recommend using conventional oil.
Cons of Synthetic Oil
Synthetic motor oils aren’t perfect. Here are some downsides to keep in mind.
- Synthetic oil is more expensive than conventional oil. Synthetic oil costs an average of twice as much as conventional oil. However, you’ll require fewer oil changes over time, so the cost differential may even out over the vehicle’s life.
- Synthetic oil may damage older engines. Synthetic oil is thinner than conventional oil, so it was initially thought to move through older engines too fast to adequately lubricate it or leak through small gaps in an older engine. However, new formulas are constantly being released that are designed for older engines, so consult your mechanic and owner’s manual for their recommendations.
- The exact blend you want may not be available at your repair shop. Each synthetic oil blend varies based on the manufacturer. You may have to shop around to find an auto shop that offers the exact blend you’re looking for, since every auto shop won’t stock every brand and blend.
7 Factors Influencing Which Type of Oil You Should Use
There isn’t a one-size-fits-all answer to whether you should use synthetic or conventional oil in your vehicle. When deciding which oil to use in your car, consider the following factors.
Manufacturer Recommendations
The manufacturer’s recommendation is the most important factor in determining which oil type to use.
Your owner’s manual will include the manufacturer’s recommended oil type, oil specifications, and oil change intervals. Violating these recommendations can damage your engine and even void your warranty.
Vehicle Age and Mileage
Many mechanics recommend using a high-mileage conventional oil for older engines with higher mileage. These formulas often contain additives designed specifically for common problems in older engines, such as aging seals and increased oil consumption.
Newer vehicles, especially those with a turbocharger, may require synthetic oil.
Operating Conditions
Conventional oil is often a good option for lighter driving conditions. However, if you frequently drive in extreme temperatures, tow heavy loads or engage in stop-and-go traffic, synthetic oil may better protect your engine from wear and tear.
Performance Requirements
High-performance vehicles such as sports cars are often harsher on engine oil than other models due to higher temperatures and other stressors.
Synthetic oil provides better lubrication and lasts longer under these conditions, making it the better choice.
Budget Considerations
Price plays a significant role in determining which oil you use in your car. Synthetic oils cost more than conventional oils, but they last longer, so the cost may even out over the life of your car.
Conventional oil is more cost-effective for most drivers, but you can opt for a synthetic blend to get some of the benefits of synthetic oil without paying as much as fully synthetic oil.
Oil Change Intervals
Synthetic oil may be a good option if you have a busy schedule or frequently forget when to get an oil change. It generally has a longer recommended change interval than conventional oil.
Whichever you choose, you must follow the manufacturer’s recommendation and your vehicle’s maintenance reminder system for oil change intervals. Failing to do so can harm your engine and violate your vehicle’s warranty.
Environmental Considerations
Synthetic oils are typically formulated to be more environmentally friendly than conventional oils. They do not create as much toxic waste since fewer oil changes are required, and they are specifically designed with lower toxicity and increased biodegradability.
Synthetic oil may also slightly increase your vehicle’s gas mileage and minimize emissions since it runs more smoothly. Some synthetic oils even have eco-friendly certifications or specifications.
FAQs.
Is a synthetic blend better than full synthetic?
No, full synthetic has the best performance of the two. However, the synthetic blend does offer some of the same properties and additives without the expense. It’s reasonably priced, a little more than conventional, but slightly lower than full synthetic.
Is it OK to use full synthetic oil instead of a synthetic blend oil?
A synthetic blend does have some of the same properties as a full synthetic. Unless your owner’s manual specifies a different type of oil, you should be okay using full synthetic. However, if you have an older model or one with high mileage, you may consider using something different.
Does synthetic blend oil last longer than conventional oil?
Yes, the synthetic blend has some of the same properties as full synthetic. It’s going to last slightly longer than conventional oil, but probably not the full term of synthetic. Check the package to see how long it is supposed to last, but always follow the recommended maintenance schedule from your automaker.
What are the disadvantages of synthetic blend oil?
There aren’t any regulations for synthetic blend oils. Therefore, it’s difficult to determine how much synthetic oil is added to each formulation. Each brand is going to function differently based on what additives are included. Plus, you will spend more on synthetic blends than on conventional oil.
When should you not use full synthetic oil?
Synthetic oil is great to use on most newer car engines. It has a lot of benefits, but it isn’t ideal for older cars, especially with a rotary engine. These motors rely on conventional oil to stay in good condition. You may also want to avoid synthetic oil if you have a high-mileage engine that needs more lubrication.
