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Disadvantages of Synthetic Oil: Synthetic Oil Explained! 

Disadvantages of Synthetic Oil: Synthetic Oil Explained! 

The synthetic oil is a manufactured lubricant that contains artificially-made chemical compounds. The said compounds are constructed by breaking down and then rebuilding the petroleum molecules. It is basically made from chemically modified materials but its base material is usually distilled crude oil. Many modern cars, especially the newer ones are getting either fully synthetic or a synthetic blend oil. Many car owners are also switching the oil of their vehicles from conventional oil to synthetic oil. However, there are some disadvantages of synthetic oil. Its disadvantages include  being more expensive than conventional oil, it limits the breaking in of the new parts of the vehicle, and it is not compatible with older car models and vehicles with rotary engines. 

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Disadvantages of Synthetic Oil:  Is Synthetic Oil Better?


Before we conclude whether synthetic oil is better or if there are more disadvantages of synthetic oil than its benefits, let us explore what synthetic oil is. Let us understand how it was made and how it works. 


Like mentioned earlier, synthetic oil is a lubricant that is made with chemical compounds that are artificially made. Synthetic oils that are good are usually made with a combination of up to three various synthetic base fluids. It usually includes polyalphaolefin or PAO, synthetic esters, and alkylated aromatics. 


If you take a closer look at the synthetic oils, regardless of their chemical combinations, you will see that they are similar. The molecular structures found in the synthetic oil are almost the same and somewhat consistent in mass and shape. The conventional oil on the other hand if put under a microscope, you will see that their molecular structures have varying shapes and sizes. The uniformity of the synthetic oil’s molecules is beneficial since it allows them to produce less friction as they run into each other. This means that it will also produce less heat. 


Since synthetic oils are artificially made, this means that the synthetic manufacturers can also modify and make designer molecules to construct an oil with properties for a specific performance. Some manufacturers mix in additives and other detergents, antioxidants, friction modifiers, dispersants, and anti-wear additives. Each synthetic manufacturer can tweak the additives amounts to ensure that the output will be the precise blend for specific environmental conditions.


Since the synthetic oil has chemical compounds that went through some process to improve its structure and performance, it now has a number of advantages compared to the conventional oil. However, just like any other tweaked and artificially-made products, there are also some known disadvantages of synthetic oil that we will discuss later on.  


There are two types of synthetic oil – the full synthetic oil and the semi-synthetic oil. 


Full Synthetic Oil


The full synthetic oil is extracted from the same crude oil as the regular oil but is processed differently. The difference in the way these oils are processed lead to a notable difference in the way and how they perform. 


Full synthetic goes through a lot of processes. It is refined, distilled and purified until it reaches a level that allows its individual molecules to be tweaked to cater the needs of the modern car engines. Because of the process a synthetic oil has to go through, this type of oil hardly has any impurities. It also tends to move more freely and can function under extreme temperatures better than conventional oil. Full synthetic oil is also known to degrade slower than the regular oil which means that it will last longer too.  


Newer vehicles that have turbocharged engines usually require their owners to use full synthetic oils. This is because these types of engines run at exceedingly high temperatures compared to the standard engines.  Vehicles that are towing heavy loads regularly, run in extreme and harsh weather conditions, and vehicles that often run into start and stop traffic are recommended to use full synthetic oil.  


Semi-synthetic Oil


The semi-synthetic oil, also known as the synthetic blend, is a combination of full synthetic oil and conventional mineral oil which means that it is capable of achieving higher intensity performance than the conventional one. By using this type of oil, you will be able to enjoy some of the benefits of the full synthetic oil but at a more affordable price. 


Since the semi-synthetic oil is a mixture of conventional and full synthetic oil, it has a performance yielding capacity that is improved and the reason for this is the synthetic part of the combination. It provides viscosity and outstandingly good performance even at colder temperatures that is usually a common issue with conventional oils.  


Disadvantages of Synthetic Oil: Is synthetic oil bad for your car?


Because there have been some reported disadvantages of synthetic oil, many are asking if it is bad for their cars. Even though the synthetic oil went through a lot of process to become what it is, it is still not perfect. Here are some of the disadvantages of synthetic oil.

  • It is more expensive. 


Its price being more expensive than conventional oil is one of the disadvantages of synthetic oil. It is already given that it will be more costly since the oil is of high quality. Plus, you also need to take into consideration its high production cost. 


The price of the synthetic oil can be a disadvantage, but if you do the computation, it can somehow become an advantage. When you use conventional oil for your vehicle, it might be cheaper than synthetic oil but it usually takes you up to 3,000 miles or maybe less. You will need to have it changed and buy a fresh, new one again. While car owners with synthetic oil are having their first interval change, most likely you will be there too, but it is for changing up your vehicle’s conventional oil for the second time. If you look at it that way, you might be able to spend less by using the more expensive full synthetic oil. 


If you really don’t want to buy the more costly fully synthetic oil and you don’t want to use conventional oil either, you can choose the less costly semi-synthetic oil. With it being a mixture of synthetic and conventional oil, you enjoy some of the perks of a full synthetic oil without spending too much. 


  • It limits the breaking in of newer vehicles. 


Both the full synthetic oil and the semi-synthetic oil is not recommended for brand new vehicles or the newer ones. This is because newer vehicles will need a certain level of friction to break in their moving parts, they usually need a lot of friction that can be supplied by using petroleum-based oil. 


Using synthetic or semi-synthetic oil in a brand new car limits its breaking in, causing the vehicle to not run efficiently as it should.  The friction resistance of the synthetic oil is the one that causes this effect. The vehicle’s moving parts will have zero or close to zero friction when you use this type of oil. It is recommended that you don’t use synthetic oil in your brand new car immediately since you will limit its breaking in and it won’t be able to run like it’s supposed to.  


Of course, you need to consult your owner’s manual first and check what kind of oil is suitable for it. 

  • It can harm old vehicle models.


Old vehicles like the ones from the year 1990 and below are not compatible with synthetic oil. This is because the synthetic oil cleans the sludge out and the old vehicles generally use deposits that act as the sealing in their oil system. While the synthetic oil is just doing what it’s supposed to, which is cleaning out the deposits, when done in the older vehicles, it will result in an oil leakage which could damage the engine. 

  • It does not work well with rotary engines. 


One of the disadvantages of synthetic oil is that it does not work well with rotary engines. The car experts do not recommend it. The reason for this is the rotary engines inject small amounts of motor oil into the combustion chamber. This is done to lubricate the apex seals. Now, burned synthetic oil can cause sticky deposits on the said apex seals. 


Disadvantages of Synthetic Oil: Is full synthetic worth it?


Although there are some reported disadvantages of synthetic oil, it can also provide a lot of benefits. According to studies, using synthetic oil in your vehicle can provide better protection for your engine. Data also shows that engines with synthetic oil performed better than the ones with conventional oil by 47 percent on different engine oil tests.


While there are disadvantages of synthetic oil, it has many advantages too. Here are some of them:


  • The synthetic oil is known to have a higher viscosity index and this can come in handy during temperature changes. Viscosity is a vital property of lubricants since it provides the film thickness or gap between metal surfaces that turn or slide against each other. This improved friction reduction can cause the engine parts to last longer since they will not wear faster and it also helps reduce the overall maintenance cost of the vehicle. 
  • When exposed to extremely low temperatures, the conventional oil tends to become thick compared to the synthetic oil. When this happens, the thickened oil will be hard to pump and won’t be able to flow effectively within the engine. This can lead your engine to be starved from oil supply which can cause an engine failure. That is why synthetic oil will be a better option if you are driving your car in extreme cold weather.
  • The synthetic oil is usually less volatile than the conventional oil. This means that it does not evaporate much like the conventional ones, making it more environmentally friendly since less oil will be emitted to the atmosphere. This can also mean that there will be less makeup oil needed between oil changes and since it does not evaporate quickly, it also lessens the risk of oil sludge. If you want to help care for the environment, then using a synthetic oil will be a better option. 
  • The synthetic oil has a longer lifespan compared to conventional oil. If the regular oil requires a 3,000-mile oil change interval, the synthetic oil’s recommended oil change interval is around every 5,000 to 7,000 miles. Some premium brands can provide an even longer interval that can go from 15,000 to 25,000 miles. However, keep in mind that no matter what oil you use for your vehicle, you still need to follow the recommended oil change interval written in your owner’s manual. 
  • The synthetic oil is known to be more efficient than conventional oil which means that it can provide a smoother and cooler engine operation. It will be able to provide more horsepower and an improved fuel economy. 

Disadvantages of Synthetic Oil: Which brand of synthetic oil is the best?

Many car owners have said that the disadvantages of synthetic oil have been outweighed by its advantages. This means that a lot of people are now choosing to use synthetic oil in their vehicles. Maybe it is due to the fact that many of the modern vehicles are equipped with turbocharged engines that usually require the use of synthetic oils. But which synthetic oil brand is the best? Based on the product reviews, performance, and availability, here are some of the best synthetic oils in 2021. 


  • Pennzoil Platinum Full Synthetic Motor Oil
  • Mobil 1 Synthetic Oil
  • Castrol EDGE Advanced Full Synthetic Motor Oil
  • AMSOIL 100% Synthetic Motor Oil
  • AmazonBasics Full Synthetic Motor Oil


Disadvantages of Synthetic Oil: Conclusion


There might be some disadvantages of synthetic oil but it also has a lot of advantages. Just keep in mind that whatever type of oil you use for your vehicle, you need to pick one that is recommended by your vehicle’s manufacturer and always follow its recommended oil change intervals. If you plan to keep your car for a long time, it is best that you invest in premium lubrication to prolong its life and all its moving parts.