Will High Mileage Oil Cause Leaks? Get The Facts

It is safe to say that high mileage oil contains a number of additives to protect engines that have seen more wear and tear. These include seal conditioners, antioxidants, and detergents.

We strongly believe that drivers whose cars have traveled 75,000 miles or more should switch to these oils. These oils also contain additives which help prevent oxidized oil from causing engine issues.

In this article, we are going to explain everything you need to know about high mileage oil and whether it cause leaks or not.

How Long Does High Mileage Synthetic Oil Last?

Synthetic oil has become a go-to choice among many drivers due to its longer shelf life and numerous advantages, such as improved engine performance and reduced friction and dirt accumulation.

However, it’s essential to recognize that oil change intervals tend to vary between vehicles and driving styles. For instance, city driving puts more strain on a car’s engine than freeway driving does.

Synthetic motor oil typically lasts 6 to 12 months before you need to replace it, unlike conventional oil which has a life cycle of approximately 3000 to 5000 miles.

If you’re uncertain about your high mileage oil type or frequency of changes, consult your service manual for guidance. It should include information on when to change it and which oil type should be used.

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Will High Mileage Oil Cause Leaks

Will High Mileage Oil Cause Leaks

No, there is actually no way for high mileage oil to cause an leak to occur, we strongly believe that It is just a myth. The thing is that High mileage oil can help slow the progression of age-related issues like blowby, cylinder slap and strange noises in your engine. Not only that but it also extends its life expectancy and delays major repairs.

Older cars, trucks and SUVs that have seen a lot of miles often need an extra boost. High-mileage motor oils with detergents, seal conditioners and antioxidants can be used to lubricate engine components to prolong their life and ensure they remain properly lubricated.

High mileage oil contains seal conditioners which expand and rejuvenate seals, reducing oil loss. Not only does this keep your engine healthier, but high mileage oils also have additives designed to reduce friction and wear.

Is Synthetic Oil Better For High Mileage Cars?

Let’s start by saying that synthetic oils contain special additives to protect against leaks, sludge and oil breakdown. Furthermore, they lubricate engine parts more effectively and keep vehicles running smoothly for extended periods.

Many of these oils are designed with high mileage vehicles in mind, providing extra protection to parts of the engine that may wear down quickly with frequent usage. Vehicles with 75,000 miles or more often benefit from these oils.

However, not all high mileage cars require synthetic oils. Older vehicles, for instance, were never designed to use these synthetic fluids in the first place.

Additionally, some synthetic blends contain a small amount of conventional oil. These mixtures may not provide the same level of performance or protection as 100% synthetic oil.

When to Use High Mileage Oil

Cars with over 75,000 miles on their odometer typically qualify as high mileage vehicles and benefit from the special antioxidants, detergents and oil additives found in high mileage motor oil.

Some high mileage oils contain seal conditioners that reduce leakage from o-rings, gaskets and valve guide seals in older engines. This helps lower oil consumption and the potential damage that could arise if an engine were to leak oil.

The oil also contains more detergents that are designed to eliminate sludge buildup. These detergents do a better job at cleaning sludge than standard motor oils, but they must be heated in order to work effectively.

However, if your car is not leaking or burning oil excessively, then there may not be a need to switch to a high-mileage motor oil. Instead, opt for a higher viscosity (thicker) conventional oil and use stop-leak additives to strengthen its seals.


As a vehicle ages, its engine parts and seals that hold it together start to break down. This can lead to leaks, especially on hot engines where seals may not be flexible enough to withstand high temperatures.

To avoid these issues, it’s best to take proper care of your car and follow a regular maintenance schedule with coolant flushes, oil changes and brake service.

Fortunately, most manufacturers offer high mileage oils designed specifically for older vehicles. These oils help reduce sludge buildup, enhance oil flow and revitalize seals and gaskets.