Synthetic Oil vs. Conventional Oil – An In-Depth Comparison

The automotive industry is characterized by diverse innovations that have evolved over the years. Just like automobiles have upgraded from one decade to another, their parts and accessories have followed the trend.

Synthetic oil vs. conventional oil is an argument that has emanated from the automotive industry’s evolution. While some car owners believe there’s no need to switch from using regular oil, others have testified about their experience with using synthetic oil.

This article explores the nitty-gritty of conventional oil and synthetic oil, especially the area of their advantages, disadvantages, as well as their differences.

Synthetic Oil vs. Conventional Oil Explained

Synthetic Oil Vs. Conventional Oil

Synthetic oil is a distinct lubricant manufactured with artificial chemical compounds that are a product of breaking down and rebuilding petroleum molecules.

This fluid is a special type of lubricant specifically derived from petroleum components that are chemically modified rather than direct crude oil. Synthetic oil is unique due to the virtually similar size and structure of the molecules in the content.

Synthetic oil is also synthesized from other raw materials; however, crude oil remains the base material. Although being the base material, the crude oil content is subjected to physical and chemical modifications.

The synthesis process and combination of various additives are the major trade secret of different synthetic oil producers like Mobil 1, Valvoline, or Castrol. Other great brands include Pennzoil platinum and ultra platinum.

Conversely, conventional oil is manufactured with whole refined crude oil. The sizes, shapes, and structures of the molecules in regular motor oil differ. This is a major drawback of conventional motor oil.

Synthetic oil can either be a full synthetic or a synthetic blend. The fully synthetic engine oil is virtually synthetic based, and it’s designed molecule after molecule with no petroleum. It also includes additives that aid the degradation of the fluid.

On the other hand, a synthetic blend consists of a synthetic stock base and regular motor oil. This mixture provides better protection and improved performance than just using conventional motor oil. You may want to take out time to find out more about synthetic oil vs. synthetic blend.

Synthetic Oil vs. Conventional Oil Viscosity

Synthetic oil features better viscosity and stability compared to conventional oil. It flows quickly during winter and resists high temperatures, sustaining the fluidity of the oil under any condition.

The viscosity grade of synthetic oil is 0W-30. However, some synthetic oil also features a viscosity grade of 5W-30, especially for warm weather.

Conversely, conventional motor oil features a relatively poor viscosity and stability, resulting in fluid thickness during cold temperatures. This automatically hinders the quick flow of the oil.

The viscosity grade of conventional oil is 5W-30. This viscosity grade is only compatible with warm weather. Many older vehicles use 5W-30 synthetic oil.

Synthetic Oil

Synthetic Oil vs. Conventional Oil Grade

Synthetic oil comes in different grades, including 5W-20, 10-W-30, 5W-30, and 15W-50. These various grades of synthetic oil are suitable for different weather conditions. For example, while 5W-20 is meant to perform well under colder temperatures, 5W-30 is designed for warm temperatures.

On the contrary, conventional oil only has a 5W-40 viscosity grade, making it more suitable for hot temperatures rather than cold temperatures.

Synthetic Oil vs. Conventional Oil Performance

Vehicle performance can be enhanced or hindered by the type of oil you use. Synthetic oil performs better than conventional motor oil. It protects a vehicle’s engine due to less friction.

Synthetic oil also contains additives that help to clean harmful deposits from contaminating the engine. The fewer impurities make the oil burn cleaner and prevent the fluid from becoming thick under colder temperatures.

Meanwhile, conventional oil is more suitable for older vehicles due to its high viscosity. It offers better lubrication, reduced chance of gear grinding, and vehicle engine wear due to the flow of the fluid.

However, synthetic oil outshines conventional motor oil when it has to do with general performance and its compatibility with both cold and hot temperatures.

Synthetic Oil vs. Conventional Oil Fuel Economy

Fuel economy is a major concern for most car owners. However, the type of oil in your car can either affect the fuel economy positively or negatively. The properties of synthetic oil automatically impact a vehicle’s fuel economy positively.

For example, the quick flow, fewer deposits, and low viscosity make a vehicle’s engine perform better, resulting in less fuel consumption.

Meanwhile, the properties of conventional motor oil hinder good fuel economy. The high viscosity that results in fluid thickness under cold temperatures negatively impacts a vehicle’s engine performance, thereby resulting in poor fuel economy.

Synthetic Oil vs. Conventional Oil Price

If you’re contemplating conventional oil vs. synthetic oil price, no doubt synthetic oil is relatively more expensive than regular motor oil.

The average cost of changing a vehicle’s conventional oil is around $38, while the cost of changing synthetic oil is about $78. This is almost twice the amount of regular motor oil.

However, changing conventional oil as a DIYer costs around $28 for 5 quarts, while synthetic oil costs $45. Irrespective of the low price of conventional oil, synthetic oil is still a better choice, especially if you can afford it.

Conventional Oil

What Is The Difference Between A Synthetic Oil And Conventional Oil?

                          Synthetic Oil                          Conventional Oil
It is made from physically and chemically modified molecules. It is made from regular refined crude oil.
Low viscosity High viscosity
More expensive Relatively cheaper
Engenders high performance at all times under any weather conditions. Only performs better under hot temperatures.
It is not susceptible to thickness under extremely cold temperatures. It thickens easily under extremely cold temperatures.
Lower contaminants help to protect the engine from sludge and build-up. Contains more contaminants, resulting in engine damage due to sludge and build-up.


Which is better, synthetic oil or conventional oil?

Without mincing words, synthetic oil is better than conventional oil. Synthetic oil features equal size molecules, which engenders better lubrication and, in turn, results in improved engine performance.

Synthetic oil remains effective and efficient, irrespective of the weather conditions. It stays slippery during lower temperatures than conventional oil. Unlike regular oil, synthetic oil does not result in engine problems due to cold climates.

If you’re contemplating which oil to use during your first oil change, synthetic oil stands as the best option. However, carefully find out from your car manufacturer’s manual.

What are the advantages of synthetic oil?

Synthetic oil is a wonderful choice for car owners over regular oil. Some of the advantages of synthetic oil include the following:

  • Chemical degradation and oxidation resistance.
  • Better flow during cold temperatures.
  • Excellent ability to withstand extreme weather conditions (cold and hot).

Synthetic oil is carefully made to suit vehicle engine requirements and external factors like weather conditions. Irrespective of your location, whether you live in the coldest part of the country or the hottest part, synthetic oil is a perfect oil choice for all car owners everywhere.

What are the disadvantages of synthetic oil?

Every coin possesses two sides; a head and a tail. Therefore, irrespective of the several advantages of synthetic oil, it also comes with its downsides. Some of the disadvantages of synthetic oil include the following:

  • Relatively more expensive than conventional oil.
  • This results in lower fuel economy when driving at high speed.
  • Possible additive separation/precipitation.

However, although synthetic oil has the above disadvantages, it is still the best choice for car owners compared to conventional oil.

It is important to compare the advantages and disadvantages of a product before making a final decision. However, in this case, synthetic oil’s advantages outweigh its disadvantages.

What are the advantages of conventional oil?

Conventional oil has some fundamental advantages that make car enthusiasts argue about its comparison with synthetic oil. Some of the advantages of using conventional oil include the following:

  • More preferred oil for older vehicle engines.
  • Highly economical and cost-effective.
  • It is not susceptible to complete damage; hence, it can be recycled.
  • Suitable for upgraded vehicles.

If your vehicle manufacturer recommends using conventional oil, ensure to stick to the recommendation. Otherwise, contact an expert auto mechanic to determine the most suitable type of oil for your car.

What are the disadvantages of conventional oil?

Remember again that every coin has a head and a tail. It is vital to examine both the good sides of conventional oil as well as the bad sides before making a final decision. Some of the disadvantages of conventional oil include the following:

  • It is more susceptible to degradation through oxidation.
  • It easily leads to engine problems like sludge deposits, corrosion, and extreme heat.
  • Circulation difficulty due to extremely cold temperatures.
  • A high tendency for smoke pollution.

If you’re contemplating synthetic oil vs. conventional oil cost, conventional oil may also become expensive when the product becomes scarce in the automotive parts markets. In any case, both synthetic oil and conventional oil have their benefits as well as drawbacks.

What happens if you put conventional oil in a car that requires synthetic?

If you’re asking, “Can you mix synthetic and conventional oil?” Of course, it’s possible. If you decide to put conventional oil in a car that already has synthetic oil, both products will blend automatically.

Of course, the mix will not cause any damage to the car’s engine whatsoever.

So, if your car currently uses synthetic oil and it’s low on oil, don’t be afraid to use conventional oil in case that’s all you can get at the moment. However, sticking to a particular type of oil is best.

Therefore, ensure to pay attention to your vehicle’s oil level in order to get a refill when necessary. With that being said, synthetic oil still stands as a better choice than conventional oil. Meanwhile, if you’re getting a replacement of oil next time, ensure to dispose of used motor oil properly.

Is it OK to switch from conventional to synthetic oil?

Of course, switching from conventional to synthetic oil is perfectly okay. Although there’s a myth about switching back and forth from conventional oil to synthetic oil; however, switching both products does not affect a car’s engine adversely in any way.

If you’re wondering, “Will the wrong oil damage my engine?” Far from that! Both conventional oil and synthetic oil are compatible. However, synthetic oil is a preferred choice for most car owners. As a matter of fact, switching from conventional oil to synthetic will improve your vehicle’s general performance.

Synthetic oil is not affected by extreme temperatures (hot or cold). Even under extremely cold temperatures, when conventional oil thickens, synthetic oil still flows perfectly.

However, if you’re contemplating synthetic oil vs. conventional oil in older cars, many older cars were designed to function better with conventional motor oil.

How often should I change synthetic oil?

You are expected to change your vehicle’s synthetic oil every 7,500 miles to 15,000 miles. However, the intervals within which you are expected to change your vehicle’s synthetic oil depend on the vehicle make and model, as well as the brand of synthetic oil you use.

Nevertheless, ensure to confirm the recommended time frame within which you must change your car’s synthetic oil from your car manufacturer’s manual. Otherwise, contact an expert auto mechanic to find out the information about when to change motor oil as it pertains to your vehicle’s make and model. Also, find out whether to use synthetic oil or regular oil.

Is it bad to use conventional oil?

Not really! All conventional oil brands do not possess the same quality. Some are relatively better than others. Some regular oil features additives that engender efficient engine performance.

If you’re considering sticking to using conventional oil, of course, it isn’t a bad idea. However, synthetic oil offers better performance and engine efficiency. It is actually more economical than buying synthetic oil.

Final Words

Understanding the clear difference between synthetic oil vs. conventional oil will help you make the best choice for your vehicle’s oil change. The advantages, disadvantages, as well as differences between synthetic oil and conventional oil, explored in this article, should help you determine your preference for the two fuel options.

If you’re currently using regular oil and you intend to switch to synthetic oil, there are a lot of benefits for you to enjoy.

Although conventional motor oil may be relatively cheaper, synthetic oil comes with more benefits. If you’re asking, “Is synthetic oil worth it?” Irrespective of the financial implication, what’s worth doing is worth doing well.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

4 thoughts on “Synthetic Oil vs. Conventional Oil – An In-Depth Comparison

  1. >>On the contrary, conventional oil only has a 5W-40 viscosity grade,

    Where did you get this idea? I’ve been buying 5W-20, 5W30, and 10W-30 in the conventional form for about 40 years now.

  2. I got a 2005 4runner from new. I tried synthetic 10 years ago and got oil leaks so I drained it and went back to conventional, and the oil leaks are mostly gone – except for a drop or two – which was what it always leaked.

    250,000 KM on the V6. 4runer runs great still.

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