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Can You Put Synthetic Oil in High Mileage Cars? (Explained)

High mileage cars are widely popular because of their higher longevity and low prices. They can cover a lot of miles and give you nonstop services but they also need standard servicing and maintenance. 

Choosing engine oil for high mileage cars is also a difficult task because they need such additives in engines that help protect seals.

Can you put synthetic oil in high mileage cars?

It’s better to avoid using synthetic oils in high mileage cars because of their low viscosity index. Though it provides higher performance to the engine, the components of the oil can damage the gaskets and seals of the engine. Also, it serves lower wear protection and lubrication to the engine.

The use of synthetic oils is dependent on the car model; certain cars prefer synthetic oils while others do not. 

However, synthetic lubricants should not be used in high-performance cars with varying models since they can compromise engine seals, reducing engine efficiency by increasing friction. 

Synthetic oils typically contain synthetic chemical components that give additional engine protection but do not provide the same level of lubrication as normal mineral oils. 

It is not beneficial to use synthetic oil in high-maligned cars because the filter must be updated. 

Synthetic oils have lower compatibility than mineral oils, resulting in leakage due to low viscosity, which is important to maintain, as well as not being compatible with engine seals, which causes leakage. 

When selecting oil for high-mileage vehicles, keep in mind that the seals must be protected. Synthetic lubricants based on esters can expand engine seals and impair tensile strength.

Again, synthetic oils in high-mileage cars might harm the gasket due to chemicals that have cleaning properties, such as detergents, which have negative engine consequences. 

Synthetic oil is thinner than other conventional oils, causing the pressure in the automobile to drop, reducing the engine’s life in high-mileage vehicles. 

In high-mileage autos, synthetic oil provides less wear protection and does not improve fuel efficiency. In high-mileage cars, however, whether synthetic or mineral oils are used, they must be changed at the manufacturer’s recommended interval. 

Though synthetic oils offer higher heat handling properties, they are more expensive than conventional lubricants when used in high-mileage vehicles.

Is synthetic oil better for high mileage cars?

Synthetic oil is not a good option for high mileage cars as they demote the engine’s life by damaging engine seals and causing oil leakage. Synthetic oil is made from the extract of crude oil combined with other chemicals and additives. 

These chemicals work to provide high performance to the car, but fail to give lubrication as much as the engines of high mileage cars need. Moreover, it can’t provide much compatibility.

For newer high mileage cars it may work comparatively well but for older high mileage cars, it’s not a good choice. Because it’s excessively rough to the seals of the engine as normally with time, the seals and gaskets become weak in older cars which will damage the seal more quickly. 

Moreover, in brand new high mileage cars, it also doesn’t work pretty well as it can’t provide as much friction new cars need and in result it lowers the car speed.

Will synthetic oil damage a high mileage engine? 

Synthetic oil shouldn’t be used in high mileage cars as it can damage the engine. Actually, it reduces engine efficiency by increasing friction when the sealants are damaged. 

Synthetic oil is made from many materials and chemicals including ester which is highly responsible for causing excessive swelling that results in oil leakage. 

Moreover, the viscosity of this oil is much thinner than other conventional oils which causes the pressure in the automobile to drop that actually damages the engine’s life. 

In addition, it serves lower wear protection to the high mileage car’s engine. The lubrication that the oil provides is not up to the mark that high mileage cars require. Moreover, it provides lower fuel proficiency. These all consequences lead to damage to the engine more quickly. 

And you’ll have to replace the engine more often which will increase your expenses as well. 

What happens when you use synthetic oil in high mileage cars? 

Here are the consequences of using synthetic oil that you may experience: 

It damages the seals of the engine and causes leakage: 

Synthetic oil is usually ester-based;  excessively rough on engine seals which lead damage in it. Actually, the compound ester causes excessive swelling that results in oil leakage. 

As synthetic oil has the ability to keep engine grime and mud free, it can damage or remove engine’s deposits which work as the sealant of your engine. 

This disturbance mostly happens in older cars because their seals, plugs or the gaskets aren’t that strong and they become fragile soon and cause leaking and burning oil. 

Decreases speed: 

Brand new cars need higher friction to run with a greater speed. But synthetic oil reduces the friction to the new vehicles which result in slower and poor speed to the new car. 

For brand new vehicles, petroleum-based oil would be wise as it helps to run properly by providing proper friction and speed. 

Increases expenses than before: 

As synthetic oil causes burning oil and hampers the seals of your car engine, you have to replace the engine more often which will increase your expenses. 

Moreover, the price of synthetic oil is much higher than conventional oil or petroleum based oil as the process of manufacturing synthetic oil is much more complicated than others. 

While petroleum based oil would cost you $20-$25, synthetic oil will cost you more than $80 which is nearly four times larger. 

How long does high mileage synthetic oil last? 

Synthetic high-mileage oil is usually more refined than conventional oil, so it lasts longer. The additives included in high-mileage oils help to protect engines from wear, allowing them to last longer. The manufacturer determines how long it will last. 

Typically, it should last three to six months, but some higher-performing high-mileage oils can last up to twelve months. 

The longevity of a high mileage oil depends on driving conditions; for example, under normal conditions, it can last ten to twelve thousand miles, but with special care, it can last twenty thousand miles. 

Manufacturers recommend changing the oil before reaching the recommended mileage. If the car owner drives eight to nine miles per day, the oil may need to be changed more frequently, the engine may begin to leak, or rattling may occur. 

As it lasts six months to years, it’s important to remember to change them within that time frame to avoid engine problems.

What oil is best for high mileage cars? 

Oils that can improve engine performance while also providing exceptional wear prevention are required for high mileage vehicles. The high mileage full synthetic oil may meet these needs, and it’ll be a great choice for high-mileage vehicles that demand more care and maintenance.

Full synthetic oil for high mileage autos offers useful compounds that prevent tiny leaks in the engine. Full synthetic oils with high mileage contain converters that improve fuel economy. Although it is expensive, the advantages far outweigh the costs.

High mileage full synthetic oil provides additional engine protection: 

The seal enhancers reduce engine leakage by increasing flexibility and, because high mileage synthetic oil has a higher viscosity and thicker consistency than other petroleum-based lubricants, they aid in seal restoration. 

The handling features of high mileage full synthetic oil provide additional engine protection, making it a popular choice among car owners with high mileage vehicles. In addition, using high-mileage synthetic oil in high-mileage cars reduces oil consumption.

High mileage synthetic blend oils for reducing engine wear: 

Engine wear is less common in high-mileage vehicles. In addition, seals are more likely to crack and leak. However, the addition of conditioners to high mileage oils minimizes seal and gasket wear. It helps to keep the engine lubricated. 

The formula of high mileage oils also prevents significant temperature variations, which keeps the temperature of the high mileage car steady. 

Final Thoughts

For high mileage cars it’s better not to go for synthetic oil as it doesn’t meet all the needs that these cars require. It has lower compatibility and efficiency compared to others. In fact, it hampers the seals of the engine and causes leakage which results in damage to the engine.