Synthetic vs conventional oil: Curious about what sets these motor oils apart?
While synthetic oil boasts purity and protection, don’t count conventional oil out yet — each has its own perks.
In this article, we’ll discuss if synthetic oil works better than conventional oil to keep your engine running smoothly and the major differences between the two. We’ll also explore how they’re made, the price difference, and their ideal oil change intervals.
Let’s hit the road!
This Article Contains:
- Is Synthetic Oil Better than Conventional Oil? (Advantages and Disadvantages)
- Synthetic vs Conventional Oil: 4 Key Differences
- How Do I Pick the Right Engine Oil for My Vehicle?
- 3 FAQs on Motor Oils
Is Synthetic Oil Better than Conventional Oil? (Advantages and Disadvantages)
Typically, synthetic oil offers several advantages over conventional oil (also called mineral oil). However, if it’s better for your car depends on several factors like your vehicle age, driving style, and your budget.
Let’s break down the pros and cons of each oil type.
A. Synthetic Motor Oil
In general, synthetic oil fairs better than conventional mineral oil by offering:
- Better performance: Synthetic lubricants maintain their viscosity over a wide range of engine running temperatures. They offer better performance in both cold weather startups and hot temperature conditions.
- Improved engine protection: Synthetic oils are engineered with advanced additives to provide better protection against engine wear, deposits, and sludge buildup.
- Extended change intervals: While conventional oil typically requires a flush every 3,000 to 5,000 miles, synthetic oil can often last up to 15,000 miles.
- Oxidation resistance: Synthetic oils are more resistant to oxidation and degradation. This means they maintain their lubrication and effectiveness for longer, even under demanding driving conditions.
- Compatibility with modern engines: Synthetic oils are formulated to meet the demands of high-performance engines with turbochargers, direct fuel injection, and other advanced technologies.
But some potential disadvantages of synthetic motor oil are:
- Higher costs (though its longer oil change interval might offset this)
- Possible additive separation at low-temperature conditions
- Slightly lower gas mileage at highway speeds
B. Conventional Motor Oil
On the other hand, conventional motor oil may not be as refined as synthetic oil, but it still has a couple of advantages over synthetic.
- More cost-effective: Conventional oils can sometimes cost half the price of synthetic lubricants. This is due to lower production costs, simpler manufacturing processes, and wider availability.
- More affordable oil change intervals: Conventional oil generally requires more frequent oil changes than synthetic oil. However, since conventional oil is cheaper, the overall cost of these more frequent oil changes can still be lower than using synthetic oil.
- Better suited for cars with an older engine: Some older engines, particularly those with higher mileage or specific design requirements, may benefit from the thicker viscosity of conventional oil.
- Less likely to cause leakage: Conventional oil’s composition, including its additives and viscosity characteristics, may be better suited to older engines and less likely to exacerbate existing leaks or cause additional engine wear.
However, the downsides of using traditional oil are:
- Prone to oxidation and degradation
- Doesn’t perform well in cold weather
- Prone to contamination by collecting engine sludge, even in new cars
- A highly toxic extraction process
Now that you know the advantages and disadvantages of each type of oil, let’s dig a little deeper into their differences to understand these oils better.
Synthetic vs Conventional Oil: 4 Key Differences
Synthetic engine oil and conventional oil are used to lubricate engine parts, slow down corrosion, prevent engine sludge, and transmit engine torque for maximized horsepower.
But, despite similar functions, synthetic and conventional engine oils have some key differences.
1. How They’re Made
Both synthetic and conventional engine oils are made from refined crude oil, but each process’s quality and complexity vary greatly:
A. Synthetic Oil
Synthetic oil is chemically produced in the laboratory by refining crude oil to get a synthetic base oil — to which various additives are added, like castor waxes and paraffinic oils.
The base oil is synthesized by rearranging hydrocarbon molecules. These synthetic base oil molecules are uniform in shape with fewer impurities between them — resulting in a highly reliable motor oil with improved stability to the oil’s structure under higher temperatures and pressures.
B. Conventional Oil
Conventional mineral oil is obtained by heating refined crude oil at various high-temperature points — leaving behind a heavier base oil. This acts as the base for conventional motor oil.
Certain additives are then added to this base oil for increased performance and engine protection. Although conventional oil protects against friction and engine wear, it’s less refined than synthetic oil.
2. Oil Viscosity Index
The viscosity index (VI) for conventional oil is 95-100, whereas, for synthetic oil, it’s above 120.
Synthetics have a naturally higher VI than conventional oil because of their additives. The higher viscosity of synthetic oil makes it capable of withstanding extreme cold or hot temperature conditions and pressures without getting affected.
But this doesn’t mean all synthetic oils work for all temperatures. If you’ve noticed, every motor oil bottle has an American Petroleum Institute (API) label printed on it. This label explains the viscosity and performance index of the oils.
3. Pricing Differences
Conventional motor oil (mineral oil) is much cheaper than fully synthetic oil.
To give you an idea, synthetic motor oil can cost two to four times more than conventional oil. For example, five quarts of conventional oil cost about $28, while the same amount of synthetic oil is around $45.
That’s because producing synthetic engine oil is costlier than other motor oil types, as synthetic oil requires advanced technology and equipment. This means it can also be expensive to maintain a regular synthetic oil change schedule.
As a result, most people often shift to synthetic blend motor oil (or semi-synthetic oil) — a combination of fully synthetic and conventional oil. Synthetic blend motor oils also act as a stepping stone when switching to synthetic motor oil.
4. Oil Change Interval
An oil change is crucial to maintaining engine performance. Let’s see how the two oils differ in this aspect:
A. Synthetic Oil
While synthetic oil does cost more, it also has a longer oil change interval.
Most vehicle mechanics and manufacturer manuals recommend getting a synthetic oil change every 5,000-7,000 miles. However, it can go as long as 10,000 to 15,000 miles if you follow good driving practices like:
- Regular oil top-ups
- Oil filter changes
- Good braking habits
- Using high-quality motor oil
B. Conventional Oil
Conventional oil, on the other hand, has a more frequent oil change interval compared to full synthetic and synthetic blend oil. This is because conventional oil is more prone to oxidation and degradation.
You can expect about 3,000-5,000 miles from your traditional oil. In best-case scenarios, it can go for about 7,000 miles without needing an oil change service.
Once your mileage exceeds the regular oil change interval, you’ll start experiencing signs of bad motor oil. If you notice dark, muddy oil with suspended impurities, you may have expired oil.
So, how do you choose the right motor oil for your car?
How Do I Pick the Right Engine Oil for My Vehicle?
Choosing between synthetic oil vs conventional oil isn’t as straightforward as it may seem. There are some essential aspects that you need to consider.
Let’s see what they are.
1. Synthetic oil
Most modern engines, especially turbocharged engines, come equipped with synthetic oil.
If your car originally uses conventional oil, you can swap it out for synthetic. But whether it’ll work or not depends on your driving style and conditions.
You can choose synthetic motor oil:
- If the engine has a relatively high daily performance (driving long distances, frequently towing heavy loads)
- If you’re living in extremely hot or cold temperatures
- If you own new vehicles with turbocharged engines
2. Conventional oil
Although a car with an older engine is more suitable for conventional oil, switching to synthetic is also possible.
But sometimes, switching to synthetic oil isn’t the best option.
- If you have low engine performance requirements (day-to-day driving)
- If you drive an older car or have purchased certified pre-owned vehicles with high mileage (75,000 miles and above)
- If you don’t maintain your car well
Whether you choose a conventional or synthetic motor oil type, remember to refer to your vehicle’s owner manual to ensure it’s safe for your car.
With the basics out of the way, let’s address any additional doubts.
3 FAQs on Motor Oils
Check out the answers to some common questions vehicle owners have about motor oils.
1. What’s the Difference Between a Full Synthetic Oil and a Synthetic Blend?
Here’s what each means:
- Full synthetic motor oil: Made entirely from chemical compounds, fully synthetic oil offers superior performance, engine protection, and longer-lasting performance. It’s generally more expensive.
- Synthetic blend oil: Also called a semi-synthetic blend, it’s a mix of conventional base oils and synthetic oils with fewer impurities. Synthetic blend oil performs better than conventional oil at a more affordable price. It’s a middle-ground option in terms of performance and cost.
In essence, fully synthetic motor oil offers top-notch performance, while synthetic blend oil balances performance with affordability. Your choice depends on your priorities and budget.
2. What is Multi-Grade Oil?
Multi-grade oil is also known as multi-viscosity engine oil. This oil flows well at low temperatures while still protecting your car’s engine at high temperatures. It’s identified by two numbers separated by a “W,” indicating its viscosity at cold temperatures (e.g., 5W) and high temperatures (e.g., 30.)
It achieves this versatility through viscosity index improvers (VIIs) — additives that adjust the oil’s viscosity based on temperature.
Multi-grade oil provides better protection, improved fuel economy, and simplifies maintenance by eliminating the need for seasonal oil changes.
3. Does Synthetic Engine Oil Improve Mileage?
Synthetic oils can improve mileage to some extent by improving your car’s engine efficiency rather than affecting fuel consumption directly.
Synthetic oils have a smoother molecular structure that helps reduce friction between engine parts, optimizing engine operation and contributing to better mileage over time.
However, the impact on mileage also depends on vehicle condition, driving habits, and engine maintenance.
Keep Your Vehicle Engine in Top Shape with the Right Oil Type
Synthetic motor oil offers more advantages than conventional oil because of its synthetic additives and better viscosity. It‘s more effective in protecting your vehicle’s engine and provides superior performance for modern engines. But don’t forget to get routine car maintenance to keep your vehicle in good shape and optimize fuel economy.
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