Synthetic Oil vs. Conventional Oil

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The choice of synthetic oil vs. conventional motor oil generally comes down to what your owner's manual recommends. In most cases, however, you can go with conventional oil, which is the less expensive option. That said, there are several benefits of synthetic oil that are worth considering.

Every gasoline or diesel engine needs lubrication. An internal combustion engine is made up of thousands of metal parts rubbing against one another at any moment. Without the lubrication provided by engine oil, your engine can't run. But knowing what kind of oil to use is another matter altogether. Generally, there are two categories: synthetic and conventional engine oil. So which one should you use?

What is conventional oil?

Conventional oil, sometimes called "mineral oil," has been used for ages in the automotive industry. This oil is made from refined crude petroleum, and the process naturally leaves behind some impurities that will affect its viscosity. Viscosity can be defined as being thick, sticky, and semifluid in consistency due to internal friction. For example, heat makes engine oil thin out, while cold makes it thicker or more viscous.

Cleaners and chemicals are added to conventional oil to help maintain a desirable viscosity level, but these additives may not work in extreme temperatures. Conventional engine oils are less chemically stable than their synthetic counterparts and can oxidize and acidify more easily, degrading the oil quality over time. Speaking of degradation, conventional oils also break down and lose their protective qualities more quickly, which means the oil must be changed more frequently. Of course, this faster degradation has the side effect of increasing the cost of maintaining a vehicle, as well as the risk that your engine could be subject to additional wear if the oil is not changed within its service interval. While conventional oil will lubricate your engine just fine, human-made synthetic oil solves many of the problems discussed here.  

What is synthetic oil?

Where conventional oil is made by refining naturally occurring crude oil, synthetic oil is made with a refining process that removes the impurities that can affect the viscosity of conventional oil. This process allows manufacturers to exert more control over the molecules making up the oil, creating a desirable level of viscosity and a more consistent oil. As a result, it can be less prone to the sludgy buildup that can occur when conventional oil is left in service for too long. Synthetic oils can also withstand much higher temperatures, which is where conventional oil begins to show signs of fatigue.

There are also synthetic blends of oil, which help balance out some of a conventional oil's liabilities by adding synthetically produced oil to the mix. These are often a cost-conscious measure because they still have the inherent weaknesses found in conventional oil.

Why you should use synthetic oil over conventional oil

As a result of its human-made qualities, synthetic oil offers a greater breadth of usability in cars. Fully synthetic oil can be produced to specifically address the needs of high-performance cars, such as long periods of time spent at high rpm, extreme temperatures, and tight engine tolerances. In addition to tailor-made oil for specific applications, fully synthetic oil offers many other advantages:

• Greater engine protection: Synthetic oil offers greater engine protection than conventional oil. A car's many parts constantly move at incredible speeds, even during regular driving. These components, as mentioned above, will wear down. However, synthetic oil provides a better protective barrier between these parts and will protect an engine's internals without breaking down.
  
• Less sludge, better in the cold: Oil will naturally congregate in certain places as it moves through your engine. If it sits undisturbed for long enough, oil will create sludgy deposits. These deposits are especially likely to occur while the oil is cold, and synthetic oil can be more fluid in cold temperatures than conventional oil. Additionally, synthetics are less likely to leave sludgy deposits overall.
  
• Higher viscosity at extreme temps: Synthetic oils offer higher viscosity more of the time. At extremely high or low temperatures, synthetic oil can better maintain its viscosity and stability, which allows it to circulate through the engine, lubricating and cooling it properly.
  
• Better for turbocharged engines: Many modern engines are turbocharged, and synthetic oils are especially ideal for engines using forced induction. Due to its more desirable viscosity, synthetic oil is better able to lubricate turbocharged engines, while conventional oils can break down even more quickly in turbocharged applications.
  
• Longer-lasting: Since synthetic oil takes more time to break down, you can go longer between oil changes. This helps reduce the amount of oil you are using and helps you avoid changing the oil too frequently.

Effective but pricey

There is, however, a kicker. While synthetic oils offer superior performance and longer service life than their conventional counterparts, they are much more expensive. This is partly why synthetic oil blends were created: to serve as a midpoint in benefits and pricing. As their name implies, these blends mix in cheaper conventional oil with synthetic oil. They can help to bring the price down while providing some of the benefits brought by synthetic oil. If you own an older vehicle using conventional oil, switching has no negative side effects, but most mechanics will also recommend changing the oil filter. Given the performance benefits and longer service life on average, using synthetic oil is still very much worth it, and using it in your next oil change or continuing to use it is one of the best things you can do for the health of your engine.

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