Should You Use High-Mileage Oil in Your Car?


Stroll down the oil aisle of a typical auto-parts store and you’ll be confronted with a literal wall of lubricant.

Dozens of brands vie for your attention and dollars with countless different types and formulations. Some promise cleaner-running engines, others boast about improved fuel efficiency and still more claim to enhance performance.

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Causing further confusion, there’s conventional and full-synthetic, plus blends of the two; there are oils made specifically for diesel engines and some for certain automotive brands. Others feature fancy-sounding metals including molybdenum, zinc and even titanium. And then there are lubricants that are supposedly tailor-made for older vehicles with lots of miles. All of this is confusing enough to make you head straight to your local dealership for service.

But let’s say you drive a well-worn vehicle, something with an odometer that’s been around the planet a few times. Is special high-mileage oil worth the extra price compared to a conventional lubricant?

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Z. George Zhang, Ph.D. and director of Valvoline Technical International thinks so. He said there are “distinct differences” compared to regular oils.

“Most of the high mileage oil will have a seal conditioner,” he said. “Normally they will have more seal conditioners in the formula.” But that’s not the only difference between them and conventional lubricants.

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“We actually talked to a lot of people with high-mileage [vehicles],” Zhang said. Their top complaint had to do with leaks. Drips and puddles on the pavement are embarrassing and unnecessary.

Different SealsHaving a car or truck that “marks its territory,” so to speak, is often the result of seal degradation. Over time the rubber components inside a powerplant can become brittle and shrink; small cracks can even form. All of this decay can lead to seepage and leaks.

“Most of the high-mileage oil will have a seal conditioner,” Zhang said. He also noted that Valvoline introduced its MaxLife product range around the year 1999 or 2000, so they’ve been on the market now for about a decade and a half.

With elastomers, a fancy name for the rubber materials seals are made from, Zhang said over time certain chemical components can leach out of them. Special conditioning compounds “tend to react with elastomers,” replacing what’s been lost over time and increasing their sealing abilities. Think of these chemicals as a salve. If your hands are dried out and the skin is cracked you can rejuvenate it with lotion, which restores its flexibility.

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“We researched a lot of these chemical compounds that can be used to rejuvenate seals,” Zhang said. He also mentioned that seal conditioners help make seals more flexible and can cause them to expand slightly, another thing that helps stop leaks.


When is the time right to start running a high-mileage oil? The folks at Valvoline recommend you make the switch at 75,000 miles. Zhang said “we use 75,000 as a typical reminder,” though you can certainly run MaxLife or a similar product beyond that, or even before.

Valvoline Oils“It’ s really good for high-mileage engines,” said Zhang, though the lubricant’s unique formulation includes more than just seal conditioners. Valvoline’s product, for instance, features extra anti-wear additives as well as additional dispersants and detergents to help break up any sludge and keep things clean.

Zhang said that when moving parts are out of tolerance, such as inside a high-mileage engine, there’s a greater chance for “metal-on-metal wear,” which is a very bad thing. He said “anti-wear materials form a sacrificial layer between metal surfaces” stopping harmful friction.

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In general terms, high-mileage oil probably costs a bit more than a comparable standard lubricant, but if your car has been around the block a few hundred thousand times, the benefits can be well worth the added expense.

For instance, the abovementioned seal conditioners can be surprisingly effective. According to Zhang “usually after two oil changes the leaking will be gone.” Additionally, he said, “some of the older vehicles tend to produce a white-bluish smoke,” which is a symptom of burning oil.

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For instance, if an engine’s valve-guide seals have gone bad, the conditioners found in high-mileage lubricants can help reduce seepage past these parts, but that’s not all.  Valvoline’s MaxLife product has a lower volatility rating, which means it’s less likely to burn in the first place. Zhang said this is “a fairly apparent thing [owners] can see after an oil change,” that is, less off-color smoke coming out of the tailpipe. Can you say instant gratification?

Engine Cut Away

But you don’t have to drive a hooptie to run this kind of lubricant. Zhang said “it’s really good for high-mileage engines… for when vehicle performance is deteriorating,” but it can be used in brand-new cars as well. Added anti-wear and detergent compounds are just as helpful in a factory-fresh vehicle as they are in one that’s got 75,000 miles on the clock. IS IT WORTH THE EXTRA COST?

Asked directly about whether high-mileage oil was worth the added expense Zhang said “absolutely; it’s for the benefit of the engine.” He also noted that regardless of when you switch it helps keep your car or truck’s powerplant “running in optimum condition longer.”

Maintaining an older vehicle and keeping it rollin’ down the road for years to come is money in the bank compared to a monthly car payment, even if you have to spend a couple extra bucks at each oil change.

The Definitive Synthetic Oil Guide

Should you put synthetic oil in a high mileage engine?

Generally speaking, it’s safe to run synthetic oil in an older or high milage engine. That’s not what you might read online though. And there’s a reason for that.

It used to be true that synthetic oil wasn’t good for older engines, namely because the additives in synthetic oils can damage the seals and gaskets. While that is true for some vehicles, it really only applies to what are essentially now classified as classic cars, or cars build before the 1990s. And the reason for that is that those older vehicles simply weren’t built to the tolerances of modern engines. As a result, the gunk and grime that might be what’s helping your seals stay sealed, could get cleaned away with a synthetic oil.

Numerous modern synthetic oils are actually designed specifically for high milage vehicles, like Castrol EDGE High Mileage.

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