Synthetic Oil Vs High Mileage: Which is the BEST for your Car?

It is important to keep your engine well lubricated with oil. This will help to protect it from wear and tear and will also help to keep it running smoothly.

The type of oil you use for your car determines how smoothly and healthily the engine oil will run.

Two of the most common types of oil are synthetic and high mileage oils. But do you know how they really operate?

Synthetic oil is a type of oil that contains artificially made chemical compounds. They can also be manufactured using chemically altered petroleum compounds instead of just using crude oil. On the other hand, high mileage oil is designed to specifically deal with the problems experienced by high mileage vehicles (in most cases above $75,000). High mileage oil will reduce smoke, emissions, and high oil consumption from old engines.

Below is my detailed comparison of synthetic oil vs high mileage and a final verdict of the best oil to use.

What is Synthetic Oil?

Synthetic oil is an artificial lubricant designed to provide superior performance and protection compared to conventional motor oils.

It is made from synthetic base stocks, which are man-made molecules that are specifically designed for use in lubricants. These synthetic base stocks can provide better performance than conventional motor oils by providing better wear protection, improved high temperature stability, and better resistance to degradation.

The oil is typically more expensive than conventional motor oil, but it can provide significant benefits in terms of engine performance and longevity. If you are looking for the best possible protection for your engine, synthetic oil is the way to go.Synthetic Oil Vs High Mileage

Advantages of Full Synthetic Oils

Withstand High Temperatures and Pressures: Full synthetic oils are made from higher-quality base oils than conventional motor oils, which means they can better withstand the high temperatures and pressures found in today’s engines. This also makes them more resistant to breakdown and helps them last longer.

No impurities: another advantage of full synthetic oils is that they don’t contain impurities that can cause deposits and sludge to build up in your engine. This can lead to decreased performance and efficiency over time.

Longer oil life: Full synthetic oils can often last longer than traditional oils, meaning you won’t have to change them as often.

Improved Fuel Economy – One of the main reasons why many drivers switch to full synthetic oils is because they can improve fuel economy. These oils are designed to flow more easily through engine components, leading to reduced friction and improved efficiency.

Reduced Emissions – Because full synthetic oils flow more easily and maintain their viscosity better than conventional oils, they can help to reduce emissions from your vehicle.

Enhanced Engine Protection – Full synthetic oils are formulated to protect engines against the increased wear and tear that can occur during extended periods of operation. This can help to prolong the life of your engine and keep it running at peak performance for longer.

Increased Horsepower – Many drivers also report an increase in horsepower after switching to full synthetic oils. This is likely due to the improved efficiency that these oils offer.

Reduced engine deposits– Full synthetic oils contain detergents and other additives that help keep engines clean by preventing deposit formation.

What is High Mileage Oil?

High mileage oil is designed for engines with over 75,000 miles on them. This type of oil has additives that help protect seals and reduce leaks. It also has a higher viscosity to protect against wear and tear.

It helps to keep your engine running smoothly and efficiently by reducing friction, wear, and corrosion. The oil also contains special additives that can help to prevent leaks and seal worn or damaged engine parts. If you have an older car that has clocked over 75,000 miles, high mileage oil may be the best choice for you.

It is important to note that high mileage oil is not a substitute for regular motor oil, and it should only be used in vehicles that are experiencing problems related to wear and tear. If you are unsure whether or not your car needs high mileage oil, consult with a qualified mechanic.

High mileage oil is available in both synthetic and conventional varieties, so you can choose the one that best suits your needs.

Does High Mileage Mean Above 75,000 Miles?

In reality, there is no “one-size-fits-all” response to this question. As stated previously, 75,000 miles (or 121,000 kilometers) is the average threshold for a “high mileage” vehicles, which is true for the majority of engines.

However, there aren’t precise guidelines for determining whether a vehicle has significant miles. Some experts argue that a vehicle with over 45,000 miles is regarded to have excessive mileage, and that with regular maintenance, a vehicle’s life expectancy is about 200,000 miles. In contrast, ordinary road cars equipped with current technology are capable of traveling up to 400,000 kilometers.


We are all aware that driving in the city differs from driving on the highway.

The consumption of gasoline and the wear and tear on the engines vary. In regards of engine wear & tear, highway miles are much less demanding than city miles, according to various studies.

Simply explained, when driving on highways, the engine maintains a constant temperature, functions at full efficiency, and starts and stops less frequently. In contrast, city miles necessitate many and frequent changes in the engine’s performance mode. This shows that engines with 75,000 city miles may be as worn as engines having 150,000 highway miles.

Obviously, there are other additional factors involved here, such as:

the manner in which the vehicle was driven, the kind and grade of gasoline and oil used, the frequency of maintenance, etc.

In light of these considerations, you must determine whether or not it’s time to begin using high-mileage oil for your engine’s condition.

Although some motorists wait until 200,000 miles, and others as earlier as 80,000 miles, the average motorist should change to high mileage oil after 100,000 miles.

Advantages of High Mileage Oils

  1. It can help extend the life of your engine. High mileage oil is formulated to protect older engines from wear and tear. It can also help prevent leaks and other problems.
  2. It can improve your fuel economy. Because high mileage oil is designed to minimize friction, it can help your engine run more efficiently. This can lead to better gas mileage.
  3. It can help reduce emissions. High mileage oil can help your engine burn cleaner, thus reducing emissions.
  4. It can be less expensive than other types of oil. High mileage oil is often less expensive than synthetic or premium oils.
  5. It is available in different viscosities. High mileage oil is available in different viscosities, so you can choose the one that’s best for your car.
  6. It helps to prevent leaks and sludge build-up and can improve engine performance and extend engine life.
  7. High mileage oil contains additives that help to seal existing leaks and prevent new ones from forming. It also contains detergents that help to keep the engine clean and free of sludge.

If you have an older car, high mileage oil can be a good choice. It can help extend the life of your engine and improve your fuel economy. Be sure to consult your owner’s manual to choose the right oil for your car.

Is Full Synthetic Oil Good For High Mileage Cars?

Yes, full synthetic oil is often recommended for high mileage cars because it can help protect engines from wear and tear.

Full synthetic oil also has superior cleaning power, which can help keep engines clean and running smoothly.

However, it is essential to consult your mechanic or car owner’s manual to ensure that full synthetic oil is the right choice for your car.

It’s also important to note that there’s been a myth that full synthetic oil is unsuitable for old or high mileage cars. The myth is highly rooted in the idea that the oil is slipperier and incompatible with seals, meaning that it will leak in areas where traditional motor oil won’t leak.

High Mileage Vs Conventional Oil

The debate between high mileage and conventional oil has been ongoing for quite some time. There are pros and cons to both types of oil, and it really depends on your specific needs as a driver needs  to decide which is right for you.

Conventional Oil High Mileage Oils
Conventional oil is the most common type of motor oil used in vehicles. It’s made from petroleum and typically lasts for about 5,000 miles before it needs to be changed.


High mileage oil is a type of motor oil designed for vehicles with over 75,000 miles on their odometers. It’s made with special additives that help protect older engines and improve their performance.


Many people believe that high mileage oil is the better choice for their vehicle, but there are pros and cons to using both types of motor oil.

If you’re driving a lot or have an older car, this could be a good option for you. However, it can be more expensive than conventional oil.

Conventional oil, on the other hand, is less expensive but doesn’t usually last as long. It’s a good option for newer cars or if you don’t drive very often.

When You Should Start Using a High Mileage Oil

Does your car leak oil? If so, it may be time to switch to high-mileage motor oil.

Using high mileage oil in your high-mileage car is one of the most important factors in maintaining the engine’s health over time. These oils differ from conventional oils in that they consist seal enhancers and specific compounds that can reduce internal and exterior engine oil leaks.

To minimize oil leaks and oil burning (which frequently occurs in older engines), experts recommend using high-mileage oil that causes the o-rings, gaskets, and seals of your engine to enlarge.

High mileage lubricants are meant to benefit high mileage engines, often those with over 75,000 miles on the odometer. And while the decision to switch to high mileage oil beyond this mileage is entirely up to the vehicle owner, many experts strongly advise you to do so.


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