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5 reasons to consider a synthetic over a conventional oil.

Ready to change your oil? If you’re wondering if you should stick with regular oil (“conventional”) or consider synthetic, we have you covered. Here’s alook at the differences between them — and why synthetic oils are well worth the extra cost.




Before we explain synthetics, let’s briefly cover conventional oil. This is the motor oil that has been used for over a century. Conventional oil is made using refined crude oil.


Synthetic oils, while more “recent,” were first developed back in the 1920s. Their popularity increased in the U.S. during the 1970s as companies focusedon increasing automotive fuel efficiency. Synthetic oils are more refined, giving them better properties than conventional oils. As their name suggests, synthetic oils are man-made using chemical compounds. The base material is typically high-quality, distilled crude oil. Then chemically modified materials are added. The process also allows manufacturers to remove impurities and tailor the oil to meet the demands of modern engines. 


A study by the American Automobile Association (AAA) found that synthetic oils out performed conventional oils by an average of 47%. The tests evaluated a range of properties, such as:

  • volatility
  • changes in viscosity
  • resistance to oxidation
  • shear stability
  • formation of deposits
  • cold-temperature pumpability
Furthermore, synthetic oils are becoming more popular. In fact, according to Consumer Reports, nearly 70% of 2019 model year cars used synthetic oil ora synthetic blend.So does a full synthetic oil make a difference? Here are the biggest advantages.



1. More resistant to extreme temperatures
Synthetics are better designed to maintain their viscosity at different, and extreme temperatures.
This helps prevent excess friction, helping your engine perform better, for longer.


2. Better engine protection

Your car’s engine parts move at high speeds. Motor oil provides an important layer of protection and lubrication between those parts. Under extreme conditions, and over time, conventional oil ismore prone to break down, leaving your engine less protected than with synthetic oils.


3. Helps prevent deposits or sludge

Conventional oils are subject to chemical degradation or oxidation. This can cause a buildup of impurities, deposits or sludge which can affect your engine’s performance. Synthetic oils contain fewer impurities, helping them resist sludge and the formation of deposits. That means a clean engine.


4. Less oil loss
Volatility is the measure of how a petroleum product vaporizes. Synthetic oils are less volatile than conventional oils, meaning there’s less oil loss over time. With conventionals, that oil loss can leave your engine less lubricated (and less protected) while increasing your need to add oil between changes


5. Longer life span = fewer oil changes

How many miles can you go on synthetic oil? You’ll be glad to know that synthetics can last a lot longer than conventional oils, with recommended changes only around every 5,000 - 7,000 miles.Products like Castrol Edge Extended Performance can even last as long as 20,000 miles between oil changes. The reason? Synthetic base oils perform better at extreme temperatures, both high and low. They also have less burn off (volatility)


These key factors are why synthetic oils are more likely to last longer — and perform better — forlonger periods of time. That means fewer changes, which saves money and helps offset the higher cost of the oil. Of course, you’ll also save time with less frequent oil changes. 


Final thoughts


People often ask “is there a downside to synthetic oil?” This most common answer is the small extra investment. A 2019 survey from AAA put the difference at around an extra $5 a month. Given all the advantages of synthetic oil, that sure seems like money well spent. Your car would probably agree.


You should always refer to your vehicle’s user guide for oil specifications and recommended oil change intervals.

You can also do a quick search with the handy Castrol Oil Finder Tool.


Data References:
Machinery Lubrication


Consumer Reports: