Can u mix conventional and synthetic oil

Here's a practical chemistry question for you: Do you know what happens if you mix regular and synthetic motor oil?

Let's say the mechanic put synthetic oil in your car when you got your oil changed. You stop at a gas station and see you are running about a quart low, but all you can get is conventional motor oil. Is it all right to use the regular oil or will you risk harming your engine by doing so?

Mixing Motor Oil

According to Mobil Oil, it should be fine to mix oils. This manufacturer states it would be unlikely anything bad would happen, such as a gel-forming from an interaction of the chemicals (a common fear), because the oils are compatible with each other.

Many oils are a blend of natural and synthetic oils. So, if you are low on oil, don't be afraid to add a quart or two of synthetic oil if you are using regular oil or even regular oil if you are using a synthetic. You don't need to rush right out and get an oil change so you'll have "pure" oil.

Possible Negative Effects

It is not recommended to routinely mix oils because the additives in different products may interact or the oils may become destabilized by the mixture. You may reduce or negate the properties of the additives.

You could lose the benefits of the more expensive synthetic oil. So, adding regular oil to your special synthetic oil will mean you'll need to get your oil changed sooner than you would have otherwise.

If you have a high-performance engine, it may not allow the (expensive) additives to work the way they are supposed to. This may not damage your engine, but it won't help its performance.

Difference in Regular and Synthetic Oil

Both conventional and synthetic motor oils are derived from petroleum, but they can be very different products. Conventional oil is refined from crude oil. It circulates through the engine to keep it cool and prevent wear by acting as a lubricant. It helps prevent corrosion, keeps surfaces clean, and seals the engine. Synthetic oil serves the same purpose, but it's tailored for higher temperature and pressure.

Synthetic oil is also refined, but then it's distilled and purified so that it contains fewer impurities and a smaller, select set of molecules. Synthetic oil also contains additives intended to help keep an engine cleaner and protect it from damage.

The main difference between regular and synthetic oil is the temperature at which it undergoes thermal degradation. In a high-performance engine, regular oil is more apt to pick up deposits and form sludge.

Cars that run hot do better with synthetic oil. For most automobiles, the only real difference you'll see is that synthetic costs more initially but lasts longer between oil changes.

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Helmenstine, Anne Marie, Ph.D. "Mixing Regular and Synthetic Motor Oils." ThoughtCo. https://www.thoughtco.com/mixing-regular-and-synthetic-oil-p2-607586 (accessed December 23, 2022).

Keeping track of the amount and quality of oil in your vehicle is an essential part of ownership. The oil works to keep the engine and all its parts lubricated, which helps it run smoothly. There are a variety of different types of oil available, but they fall into two general categories. Here we will take a look at conventional oil and synthetic oil and see if you can mix the two together.

What is Conventional Oil?

Image via Flickr by JeeperMedia

Conventional motor oil is a lubricant that comes directly from crude oil. It has properties that allow it to provide lubrication for the engine at very high temperatures, and it will maintain its stability over a long period of time. Conventional oil was first used in the late 1800s for steam engines and was later used for many other machines. 

Conventional oil is often more economical than synthetic since it doesn't require as much re-engineering and refining. Both of these can be expensive processes, which often increases the price of synthetic oil. Conventional oil still contains the important additives needed to reduce engine wear, and it has the power needed to clean away sludge and keep new sludge in the oilways from forming. 

What is Synthetic Oil?

Synthetic oil is also a lubricant, but it is made from artificial chemical compounds. To make synthetic oil, petroleum molecules are broken down and rebuilt to create a standardized compound. The molecules in base synthetic oil are all the same size and structure. This is different from conventional oil, which, since it comes from crude oil, has molecules of many sizes, structures, and shapes. 

Synthetic oil can be completely synthetic or a blend of different base types. Full synthetic oils have a base stock and are created without the use of any petroleum. These oils have additives that help reduce the degradation of the oil. Some synthetics use a blend of conventional oil and a synthetic base stock. Combining the two gives the engine some extra protection than it would get with just the conventional oil. 

Can You Mix Conventional Oil With Synthetic?

The short answer is yes. There is no danger or risk of combustion, and mixing the two types of oil won't harm your engine. However, it's important to note that if you do mix the two, the conventional oil can keep the synthetic from performing to its fullest potential.

It is not harmful to mix oils, and you don't run the risk of causing a chemical reaction. Some of the synthetics are already a mix of conventional and synthetic, so essentially it is already combined.

Even though you can mix the two, most mechanics will not recommend that you do it regularly. The additives in the different types of products may interact, or the mix of two different oils may cause the mixture to become less stable, and you might lose the benefit of the synthetic. If you have a vehicle with a high-performance engine, mixing conventional with synthetic might not allow the expensive additives in the synthetic to work the way they should. It won't damage the engine, but it won't help it either. 

The Benefits of Synthetic Oil

Synthetic oil has some benefits you don't get with regular oil. There are some excellent reasons to use it, but it is not always necessary to spend the extra money.

Synthetic oil is designed to:

◾️Resist breakdown. This makes it last longer than conventional oil, so you don't need to change it as often.

◾️Withstand higher temperatures. This allows it to keep engines running longer.

◾️Flow in cold temperatures. This reduces engine wear when starting a car in cold climates.

Some driving situations may benefit from a synthetic. Its ability to resist breaking down will help prolong your engine's life depending on where you live and if you drive long or short distances on a regular basis. If you make a lot of short trips, conventional oil might not get warm enough to burn off impurities and moisture, and if you live in an area where it gets cold in the winter or has extremely high temperatures in the summer, synthetic oil does a better job than conventional oil of protecting the engine. 

Synthetic oil is also better if you have a vehicle with an engine that tends to have sludge buildup. This sludge can block oil passages and lead to engine problems. Synthetic oil is less likely to allow the sludge to form. 

Another benefit of synthetic oil is that it is better for the environment. Since it is created and not harvested from the ground, it is more eco-friendly than conventional oil.

The Benefits of Conventional Oil

As mentioned before, conventional oil is easier to find, and it is cheaper than synthetic. Even with synthetics becoming more popular, you are more likely to find regular oil on the shelves at the store. Conventional oil is often recommended for older engines. Since synthetic flows more smoothly, it moves faster. The slower flow of conventional oil means the engine gets more lubrication, and this is often beneficial for older engines. The extra lubrication helps them last longer.

Older engines are not designed for synthetic oil, and if you use it, you even run the chance of it seeping out it the gaskets or even into the combustion chambers.

How To Decide Which Oil To Use

The best way to determine what type of oil to use is to look at the manufacturer's guide. If you dig out your owner's manual, it will state what type of oil is best for your vehicle, and you can also look on the oil bottle. It will state what types of engines it will work for. 

If you have other questions about synthetic and conventional oil and whether or not you can mix them, give us a call at United Chevrolet Buick GMC. We will happily answer all of your questions and even help you determine which one you should be using. 

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