Which type of oil is most suitable for high-mileage vehicles?

High-mileage vehicles typically have more than 75,000 miles on their odometer, and these engines often experience increased wear and tear. High-mileage oils are specifically formulated to address the unique needs of older engines. They contain additives that help to reduce engine wear, restore flexibility to engine seals, and minimize oil consumption, which can be common in vehicles with higher mileage.

The formulation of high-mileage oil includes special conditioners designed to rejuvenate aging seals, which helps prevent leaks and maintain proper oil pressure. Additionally, these oils can enhance the overall performance and longevity of the engine by providing better engine cleanliness and reducing the risk of sludge build-up.

While conventional oil, full synthetic oil, and diesel engine oil have their uses, they may not provide the specific benefits required by high-mileage engines. Conventional oil does not have the enhanced protective additives that high-mileage oil does. Full synthetic oil, while often superior in performance and protection, might not be necessary for older engines unless they are specifically designed to run on it. Diesel engine oil, on the other hand, is formulated for the requirements of diesel engines and is not suitable for gasoline engines typically classified as high-mileage.

Therefore, high-mileage synthetic or conventional oil is the best