How to Change Your Oil

What Is The Best High Mileage Oil?

If you’re just browsing and want a quick answer, Castrol EDGE full synthetic is the best high mileage oil. I noticed increased power and reduced engine noise.

I can remember my father telling me when I was still in elementary school: If you took care of a car, a good one would last you 100,000 miles.

It’s interesting to note that my father always traded in his vehicles once they hit the 50K mark. I can remember thinking that putting 100,000 miles on a vehicle would take forever.

I quickly discovered how fast you can rack up those miles, after putting 300,000 on a work vehicle within about 18 months.

When I worked for a car manufacturer, I noticed many of the mechanics had older vehicles in which they used a high mileage motor oil. I often wondered if they were worth the extra money.

Do High Mileage Oils Make any Difference?

My father was right about one thing. Regular maintenance, especially oil changes, was vital for keeping a car on the road as long as possible.

With the average car owner keeping their cars, SUVs, and trucks for an average of 11.8 years, those vehicles must have packed on some serious mileage. This got me thinking. Do those high mileage oils have any real value or were they simply a marketing scheme?

What is a high mileage vehicle? That would depend on who you ask, but many say somewhere in the area of 75-100,000K. Many modern vehicles easily reach 200K. Maybe a high mileage oil would make a difference.

The Basics of Motor Oil

In addition to lubricating and cooling the engine, motor oil plays a vital part in keeping the engine clean. It also prevents rubber seals from drying out.

This is why engine oils contain additives, some as much as 30 percent of the overall weight of the oil. When it comes to high mileage oils, you can bet that they have extra additives.

Those extra additives include:

Seal Conditioners – Time and mileage, combined with the heat generated by the motor, will cause seals and gaskets to become hard and brittle. This makes them shrink and no longer seal the motor like before. The seal conditioners used in high mileage oils are designed to soften these parts and make them swell a bit. This helps them to perform the way they did before. It won’t make your car run like new, but you should notice a difference.

Anti-Wear Additives – These bond to the metal surfaces in the motor which prevents excessive wear.

Extra Detergents – It might sound strange to think of detergent in your motor oil. Without this, the filter would not be able to remove all the sludge and contaminants that are in the motor. A clean motor runs much cooler, and more efficiently.

There are Limitations to High Mileage Oil

A high mileage oil is great at preventing minor oil leaks due to leaking seals. It gives your motor a little extra power and helps it to last a bit longer. It’s important to note that these oils do have limitations.

A high mileage oil will not solve major engine problems, such as worn rings, rod knock, blow-by, or piston slap. These types of problems require major engine repair.

I’ve tried many of these high mileage oils. I have seen them stop some minor oil burning (smoke out the tailpipe). Some even stop some very minor leaks, such as from a rear main seal. But if you are adding a quart of oil every other day, don’t think any of these oils will solve those problems.

Valvoline High Mileage

This is a synthetic blend motor oil that is available in the weights that most cars use, including 10W-30 and 10W-40.

Valvoline is a well-known name and the one my father used, coincidentally. It contains seal conditioners, extra detergents, and wear protectors. What I found interesting was that it also contained antioxidants. I always thought of antioxidants for the human body. But when used in motor oil, it prevents the oil from breaking down and leaving deposits.

Valvoline considers any engine with 75K to be high mileage. First off, I loved being able to buy this in a 5-quart bottle with a no-glug tube. That glug, glug, glug always makes me spill some oil, so this little thing made my day right at the get-go. I have used this oil and I can vouch that it keeps seals and gaskets pliable.

This oil gets plenty of positive reviews on all the major online sites and it’s easy to see why. Many people state that this oil stopped minor oil leaks. Some noted that it took a minimum of 2 oil changes to feel any real difference in power.


  • It will keep seals and gaskets pliable
  • It stops minor oil leaks
  • The “no glug” 5-quart jug is a small but nice addition.


  • It might take 2 or more oil changes to feel the results.
  • Some complain that the oil smells burned after only 3,000 miles.
  • This is a synthetic oil blend and is not recommended for all makes and models.

Pennzoil High Mileage Conventional

Pennzoil might have the biggest name recognition on the planet. Like Coke, it feels as if you can ask for Pennzoil and the name is known in any language.

Like Valvoline, Pennzoil considers any vehicle over 75K to be a high mileage one. This oil is a conventional oil, which means it contains no synthetics and can be used on every type of vehicle.

Pennzoil high mileage oil comes in almost every weight imaginable, including the harder to find oil weights, such as straight 30w.

The company states this oil is designed to prevent sludge. They use Fortified Active Cleansing agents which prevent the formation of deposits. The product does not say that it helps to keep seals pliable or prevents minor oil leaks. It does say that it can increase gas mileage by preventing the build-up of sludge.

Pennzoil high mileage oil mostly receives high ratings, but no one seems to be overly impressed by this product.


  • This conventional oil can be used in all cars.
  • It has a name known for quality that most people trust.
  • Some state that their engine runs quieter using this oil.


  • It doesn’t appear to be much different than their regular oil
  • Contrary to above, other users state that their engines make more noise than before.

Royal Purple HMX High Mileage Synthetic

If you are one of those who don’t mind buying brands you have never heard of, this is a find you will enjoy. Royal Purple comes in a large 5 quart proudly purple jug.

Designed for vehicles with 75K or more, this high mileage oil has a phosphorus zinc additive that prevents excessive wear.

The initials HMX is the manufacturer’s proprietary blend of additives. It softens seals that have become hard with age and reduces oil consumption.

Like Valvoline, this oil also has oxidation resistance. It also has an ionic attraction to metal surfaces. The company says will minimize wear on start-up.


  • Offers easier starting for most users
  • Positive results were noted after a single oil change


100 percent synthetic motor oil may not work in all vehicles

Tends to be more expensive than most name brands

AmazonBasics High Mileage Full Synthetic

This is a full synthetic motor oil designed for engines with more than 75K. The full synthetic high mileage oil only comes in weights from 5W-20. 5W-30, and 10W-30. For other weights, you can use their high mileage synthetic blend.

Like other high mileage oils, AmazonBasics has a formula that is designed to reduce friction, prevent sludge and corrosion.

Unlike other high mileage oils, it doesn’t say anything about additives to soften seals and gaskets.

It has positive reviews but no one seems overly impressed.


  • It’s less expensive than other brands
  • It’s a good value for a synthetic oil


  • Numerous people complain about a lack of window on the 5-quart bottle. This would enable users to see how much oil remains in the container.
  • No apparent engine performance improvement.
  • It’s a good value, but nothing exceptional.

Castrol EDGE High Mileage Full Synthetic

Here is another brand name that has a solid reputation behind it.

Castrol High Mileage Edge is a high mileage oil designed for vehicles with more than 75,000. This is a fully synthetic oil that contains Castrol’s Fluid Titanium Technology. It’s supposed to transform when under pressure. It will temporarily create a cushion between surfaces which reduces friction. Whenever friction is reduced, performance is improved.

Nearly everyone raves about how they noticed more performance within one or two drives after changing the oil, not one or two oil changes like the others.

Not only does this oil appear to improve performance, but also minor engine noises. Piston slap and lifter tapping were dramatically quieter.

It’s hard to ignore an oil that has been successful in quieting major engine noises. I had to try it myself in my old rig and I can attest that this oil is nothing short of amazing. My SUV has 150K. No major problems, but you can’t help but notice the increase in power soon after changing the oil. I would rate this oil a 10 if I could.


  • It reduces all types of engine noise dramatically.
  • There’s improved performance after a few drives
  • It costs no more than other brand name synthetic oils


  • Fully synthetic oils aren’t compatible with all vehicles
  • Only available in 5W-30 and 5W-20 at this writing.

The Bottom Line

Everyone has their favorite brands. If you are happy with the brand of high mileage oil you are using, keep using it!

For my money I would have to go with the Castrol EDGE full synthetic motor oil.

I’ve been a Valvoline guy all my life and that no-glug bottle is a big plus. There is no denying that Castrol was the clear winner.

Any oil that can stop piston slap has something special in it. I personally felt a big improvement in performance in my old SUV, and I’m not alone in that.

I can’t remember being excited about a motor oil before. But I cannot wait to see if the next oil change brings anything new out of the engine.

Price varies, of course, depending on where you live and where you buy it. In my area the Castrol is very close in price to the Valvoline. Yes, it does cost more than the AmazonBasics, but no one seems to be raving about that oil like they do with the Castrol.

My only suggestion would be Dear Castrol, please make a no-glug bottle for all us clumsy folks.

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