regular oil vs high mileage – does high mileage oil make a difference?

There are a lot of arguments surrounding the specified use of high mileage synthetic oil and regular synthetic oil. The rumors are that regular synthetic oils are slippery; they have lower viscosity levels and are not the perfect choice for high mileage cars. 

It is important to note that the type of oil that you choose for your vehicle determines the overall performance of the car. From mileage, and level of seal protection, to leaks prevention, you need to choose an engine oil that matches your vehicle’s needs.

The core difference between high mileage vs synthetic oil is that High mileage synthetic oil is designed for older engines to fix leaks and failing seals. This is compared to regular synthetic oil that is the default choice for every new vehicle.

High Mileage Synthetic oil vs Regular Synthetic Oil

high mileage synthetic oil vs regular synthetic oil – which one to choose?

The comparison between high mileage oil vs synthetic is a close tie. Both products are good for different purposes, so it is difficult to choose one above the other.

High Mileage Synthetic oil is a great choice when your engine is old and experiencing a lot of problems. However, you don’t need to use a high mileage synthetic on a new seal to avoid tightening it too much.

I will prefer regular synthetic oil except the engine is an old one that needs intense care or the engine is a high mileage engine that needs to reach more than 75,000 miles.

what is High Mileage Synthetic oil?

High mileage synthetic oil is the type of oil specially designed for high mileage engines. These engines run more than 75,000 miles. To maintain the performance of your high mileage engine, it is essential to use engine oil that matches its needs. 

High Mileage Synthetic engine oils are designed to handle the needs of your high mileage engine. High mileage synthetic oil comes with additives, detergents, conditioners, and seal enhancers that reduce leaks, remove engine sludge, and sustain low oil consumption. 

It is a great choice for old engines. You should switch to high mileage synthetic oil when your engine starts loosening or displaying signs of leakage. High mileage synthetic oils have seal swells and conditioners that swell the o-rings, seals, and gaskets, reducing the possibility of a leak.

Features of High Mileage Synthetic Oil

1. Conditioners and Additives

High mileage synthetic oils have conditioners and additives that positively impact the performance of the engine. The viscosity modifiers in this oil improve its durability by preventing the easy loss of viscosity. The antioxidants increase the oxidative resistance of the high mileage oil, while the detergents remove sludges that buildup in the engine after extended usage.

2. Oil Economy

Oil leaks can cause an increase in oil consumption. High Mileage synthetic oils fix this by preventing oil burn-offs and improving the state of the weak seals.

3. Engine maintenance

High mileage synthetic oil provides optimal engine maintenance by offering engine protection against wear and tear. This improves the state of critical parts of the engine.

what is Regular synthetic oil?

Regular synthetic oil is made from a base of chemically modified elements. Base oil that contains additives, zero mineral oil content, carefully enhanced to impact the performance of the engine. 

There are great similarities between regular synthetic oils and high mileage synthetic oil. This is visible in the ability of regular synthetic oil to combat sludge, engine protection against wear, tears, and high temperatures.

Regular synthetic oil boasts of a greater resistance but high mileage synthetic oil has a larger amount of seal swellers. This presents a great advantage for cars with seal problems. If your car doesn’t have seal problems, regular synthetic oil is the best option. 

It is inadvisable to use high mileage oil on a new seal or an engine that is still in good shape. This will tighten the seals. 

Regular synthetic oil is the default choice for most vehicles before they start developing problems.

Features of Regular synthetic oil

1. Engine Protection

Regular synthetic oil is not as refined as high mileage oil, but it pretty much offers a greater amount of engine protection than conventional oil. Regular synthetic oil includes additives that prevent the breakdown of oil, while also sustaining the removal of sludges.

2. General Use

Synthetic Oils are the go-to choices for every new vehicle. They are built with a higher refined base oil, a higher oxidation and acidification resistance, and more chemical stability. 

3. Lubrication

Regular synthetic oils have low viscosity. This enhances lubrication and allows a smooth and faster flow of oil in the engine even at low temperatures.

Differences between high mileage oil vs synthetic oil

FeaturesHigh Mileage Synthetic OilRegular Synthetic oil
Miles75,0007500 – 10,000
General UseHigh Performance and Old Engines with problems (showing signs of wear and tear)High Performance and new engines
LimitationsLimited to specified vehiclesNo Limitations

#1- Miles

The number of miles of engine oil refers to the amount of time you should use them before thinking of replacing them. High mileage synthetic oil lasts up to 75,000 miles. This is greater than the 75000 – 10,000 benchmark for regular synthetic oil. 

Winner: High Mileage Synthetic Oil

#2- Viscosity

High mileage synthetic oil has a higher viscosity level. They are usually thick because the old engines will perform efficiently with thicker oil. This is contrary to a regular synthetic oil that is thinner, with a more lubrication flow.

Not minding the fact that the viscosity index of these oils differ according to their base oil category, both oils are built to the specifications of the engines.

Winner: Both

#3- Best Use

Regular Synthetic oil works in every vehicle and engine. High mileage synthetic oil is limited to older engines. While high mileage synthetic oil is meant for vehicles with the need to reach more than 75,000 miles, regular synthetic oil is good for vehicles within 7,500 – 10,000 miles. 

Regular synthetic oil contains additives just as high mileage synthetic oil, but additives are not used as the selling point for regular synthetic oil like it is used in high mileage oil. The additives in both oils enforce sludge removal, but high mileage oil has more seal conditioners that address leaks.

The truth is, these oils are great in different conditions.

Winner: Both

key Similarities between Regular and High Mileage oil

1. Engine Protection

The formula of high mileage and regular synthetic oil improves the durability of the engine. Protecting the seals, and gaskets also prevents oil leaks. This extends the life of the engine and also enhances its performance.

Regular synthetic oil employs a low viscosity that allows the free and faster flow of oil in new engines. High Mileage synthetic oils have a higher viscosity, thicker to protect the engine components. They work in different ways, but the end solution is to protect your engine and keep it in good form. 

2. Lubrication

The lubrication effect of high mileage and regular synthetic oils are not the same, but the results are similar. This works together to ensure fuel and oil economy, directly impacting the car’s performance.

Regular synthetic oil is thinner because of the need to lubricate quickly, the use of thick high mileage oils is to offer frictional resistance and prevent oil loss.

3. Additives

Detergents, coolants, friction modifiers, antioxidants, anti-foaming, and viscosity improvers, high mileage, and regular share almost the same additives with similar functions. The percentage of additives in regular and high mileage will vary, but the purpose remains.

Frequently asked questions (FAQs)

1. When should you use High Mileage synthetic oil?

You should use high mileage synthetic oil for high mileage engines. High mileage synthetic oil is required when your vehicle needs to reach 75,000 miles or above. It is also a good option for old engines experiencing oil leaks and engine loosening.

2. Is it okay to use synthetic oil in high mileage cars?

Yes, it is okay to use synthetic oil in high mileage cars. Contrary to popular opinion, synthetic oil will not damage a high mileage engine. 

You will come across some reports that insist that it is not safe to use synthetic oil in high mileage cars. I wouldn’t disprove this fact. Some high mileage engines don’t work well with synthetic oil. 

You must confirm that the synthetic oil doesn’t have additives that will affect your high mileage engines.

3. Does high mileage synthetic oil make a difference?

Yes. High Mileage synthetic oil helps in addressing leaks and burnoffs. High mileage synthetic oil helps improve weak seals and improves the oil economy.

Regular Oil vs Synthetic Oil >> Check out the video below:


The way you use your car determines the number of miles that your engine oil will last before changing it. Choosing between high mileage synthetic oil vs regular synthetic oil should boil down to why you need them and the need to achieve the best performance for your car.

If you are using an old engine or car model, a high mileage synthetic oil is a good choice. If you must use regular synthetic oil on an old or high mileage engine, you must confirm the compatibility or seek professional aid.

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Mahir Ahmed


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