When do i use high mileage oil

The first is to switch when your vehicle reaches 75, miles. The second is to switch if your older vehicle is beginning to show signs of engine loosening. What makes high-mileage engine oils different? High-mileage oils have ingredients to take care of older engines, like conditioners, seal swells, antioxidants, detergents and wear or friction additives. These oils need to stay thicker longer to protect engine parts.

Over time, anything mechanical—even door handles—begins to loosen. Protection from damage: High mileage vehicles tend to suffer from more general wear and tear than younger cars. The additives in high mileage oil preserve and protect your entire engine. I'm ready for my high mileage oil change! Up Next. Theres more to motor oil than a dipstick. Learn how to check your oil at home and help keep your engine running smoothly, with Firestone Complete Auto Care. Motor oil is motor oil, right?

Not quite. Check out top synthetic oil benefits and find out if synthetic oil is right for you, with Firestone Complete Auto Care. Whats the best motor oil for summer? The answer might surprise you. Find out, before your next oil change at Firestone Complete Auto Care! Find Store.

Find a Different Location Find a Store. Do you want to change your Preferred Store? Yes No. This site uses cookies to enhance your user experience. An engine that has been well cared for , with all the scheduled maintenance performed, should be able to support longer intervals between oil changes.

As an engine is broken in, the sharp little edges and rough surfaces become polished down, enabling the surfaces to mate better and lessening the chances of metal-to-metal contact assuming full-fluid separation at the operating temperature.

A caveat to this would be when there is wear in the cylinders and on the rings, which may allow blowby. If you know what you are looking for, a comprehensive oil analysis test slate may not be necessary. A simple blotter spot test may be enough to determine if you have fuel dilution or coolant in your motor oil.

To help you decide if your high mileage oil change intervals can be longer, consider the following advice:. If your engine burns oil or you must add oil to it at regular intervals, you should not try to extend your oil change. If you have performed a compression test on your engine and found that you are losing pressure, you should avoid extended oil change intervals.

If you are not using a quality filter, you should not extend your oil change. Reconsider the filter you are using, as it will have the greatest impact on engine life.

The better the oil is filtered, the longer the engine and oil will last. If switching from a conventional mineral oil to a synthetic oil, you may have issues with leakage depending on the synthetic used and the types of seals in the engine. This could be caused by seal incompatibility or residue buildup being cleaned out of areas where it was previously sealing a leak. Synthetic oils have advanced over the years, and motor oil manufacturers are taking this into consideration, so this issue is becoming less of a problem.

As fuel-economy standards change and new technologies and engine metallurgy are introduced, the classifications for engine oils must also change.

With this in mind, it is important to read the labels on the oils you buy for your vehicles. For four-stroke road vehicles running on diesel engine oil, the most current category is CK For low-sulfur diesel engines manufactured in or later, you may need an engine oil classified as FA This classification indicates that these oils have been specifically formulated to reduce greenhouse gas GHG emissions. These new motor oil classifications are backward compatible, so using a newer category oil on an older vehicle should not create any issues.

Yet, what can cause problems is operating a newer vehicle with an older service category engine oil. Using a high-mileage oil in a new vehicle would be ill-advised, since no manufacturer recommends this type of oil for a new vehicle. Would it harm your engine?

The information assembled below is based on data obtained from the SDS for 10W oil from nine of the most popular engine oil manufacturers. Castrol GTX. Valvoline MaxLife. Royal Purple HMX. They have a viscosity index greater than or equal to 80 and less than using the test methods specified in the table below.

Group II base stocks contain greater than or equal to 90 percent saturates and less than or equal to 0. Group III base stocks contain greater than or equal to 90 percent saturates and less than or equal to 0. They have a viscosity index greater than or equal to using the test methods specified in the table below. The following key properties must be met in the substituted stock: kinematic viscosity at degrees C, 40 degrees C and degrees C ; viscosity index; NOACK volatility; pour point; and unsaturates.

Conventional motor oil begins as crude oil from the ground. This type of mineral base oil carries additives well due to its molecular structure. Yet, it does have a shorter lifespan when compared with synthetic oil and will have a lower viscosity index than a true synthetic or Group III mineral oil.

Although Group III oils originate from a mineral oil, they undergo such high refining that they hold properties very similar to a true synthetic oil. Synthetic oils generally are more resilient against temperature extremes and sheer than conventional motor oils due to their molecular structure and uniformity.

One of the drawbacks of synthetic oils is that although they tend to have higher oxidative stability, they may not hold additives in suspension as well as a less refined oil. Conventional and synthetic oils may be mixed so the mineral oil can hold additives in suspension while relying on the synthetic for scrubbing capability and oxidative stability.