What’s The Difference Between Conventional Oil and Synthetic Oil?

There is a lot of confusion out there over the difference between synthetic oil and conventional oil. While synthetic oil comes with a higher price tag, there are other significant differences you should be aware of.


Each of these oils comes with its own set of pros and cons and knowing these will make it easier to decide which oil is the best choice for your vehicle.



What is Conventional Oil?



Conventional oil is an engine lubricant refined directly from crude oil using special chemical compounds. As it has long been the standard for engine lubrication, conventional motor oil can tend to break down with wear and heat much sooner than synthetic varieties. This leaves the oil dirty and unable to perform for extended periods. For that reason, conventional oil needs more frequent attention through engine oil changes.



What is Synthetic Oil?



Synthetic oil is partially, if not completely man-made, depending on the brand. The semi-synthetic oil, or synthetic blend, has a mixture of petroleum-based products and manufactured lubricating additives. A full synthetic oil is completely manufactured to enhance performance and the level of quality without the use of any crude oil products. Some engine oil manufacturers claim to be synthetic on their packaging but they, in fact, use petroleum products, which can cause some confusion.


Because of the special additives, synthetic oil has certain advantages over conventional oil including:



  • Higher temperature thresholds to maintain lubrication and viscosity under extreme conditions
  • Fewer contaminants for a cleaner and more refined oil
  • The cleaner oil produces less friction and therefore heat, for a longer-lasting engine
  • Reduced engine sludge
  • Cleaner burning synthetic oil better protects the engine
  • Easier engine start



As synthetic oil runs smoother, cleaner, and hotter than conventional oil, it typically lasts longer too. As a result, fewer oil changes may be needed depending on your vehicle model. It also allows for longer engine life, saving much more money in the long run, with less frequent vehicle upgrades.



Synthetic Vs. Conventional



It is very difficult to tell the difference between a conventional oil, a semi-synthetic, and a full synthetic oil by visual inspection alone. Where it becomes noticeable, is in how they are made and in how they perform.

With use, conventional oil tends to become thicker, darker, and dirtier in your engine, leading to the buildup of sludge that compromises your engine’s performance.


Synthetic oil, whether it’s semi or full synthetic, tends to be better for the engine with fewer impurities and less friction, even at high temperatures. Also, the additives ensure a cleaner system, reducing the amount of sludge buildup.


The best engine oil you can get for your vehicle is full synthetic oil. In fact, some vehicle manufacturers recommend using a full synthetic oil for their vehicle engines.


However, conventional oil does not need to be avoided. As the cost of synthetic oil tends to be higher, it can be a factor in the decision making process for many drivers, especially those who own older vehicles. A synthetic blend may be an option to achieve that higher level of performance without being too costly.


Changing from conventional to synthetic oil is easily done without doing harm to your engine, so the choice comes down to what your vehicle manufacturer suggests and your own preference. Note, however, that when using synthetic oil for your engine, you will need a special oil filter with a reduced micron rating.