Amsoil vs Redline vs Royal Purple – What the best? (Detailed Comparison)

There’s been a great deal of debate in the blogosphere about motor oil in recent years. Part of the reason for this has been a growth spurt in the industry, which has led to the fiercest competition to produce the most high-quality motor oil on the market. Technology has made it possible to strive for such goals, and companies have taken up the challenge. 

Companies are now capable of synthesizing the oil in a laboratory, ensuring problems like starting your engine in freezing temperatures will be a thing of the past. 

Of the products out there, the biggest competitors in high quality, superior motor oil products are Amsoil, Royal Purple and Redline. All three are made by respectable brands, so how can one be preferable to the other? In this article, we’ll go over the three options and try to find the best. 

 Amsoil, Redline, and Royal Purple – How Do They Compare?


One of the key focuses when choosing a motor oil is how often you’re going to need to replace it. This is often the deciding factor, as it speaks to how much you’ll need to budget for motor oil every year. 

Conventional motor oil requires changing typically every 5,000-7,500 miles, but synthetic oils can prolong the mileage much longer. In Amsoil’s case, normal service changes should take place every 25,000 miles.

Redline lists its changes to be scheduled every 18,000 miles. And coming in last, Royal Purple recommends 12,000 miles. 

Ideally, the option that is going to cost you less in the long run is usually your best choice. And Amsoil appears to be the brand that needs changing the least often, saving you a small fortune. At least when it comes to frequency of change, Amsoil is the winner. 


But the money you save from refilling the oil less frequently isn’t going to mean that much when the oil itself is expensive. In terms of how much you’re paying in stores, Royal Purple appears to be the cheapest of the three. 

But one should note that it’s also the one you’re going to fill up on most frequently, so you’ll have to do the math yourself to decide whether or not buying the cheapest is saving you money. You may end up spending more in the long run on more bottles of Royal Purple rather than one, expensive Amsoil. 

Motor Oil Tests

Motor oil tests are easy to ignore. Most of us don’t quite understand the process anyway, so we don’t take much stock in it. But nevertheless, some manufacturer’s still adhere to them. Here are a few of the most relevant. 

Total Base Number

The total base number is found by measuring the alkalinity, which is especially important in removing acid deposits from your engine. The higher the base number, the more likely it is to help fight the corrosiveness of the acid buildup. 

Amsoil currently has the highest base number, followed closely by Royal Purple. 

Cold-Cranking Viscosity Test

Viscosity is the thickness of your motor oil. This test discovers the number related to the engine’s ability to start in cold temperatures. The lower the value, the easier it’ll start in cold temperatures. 

Amsoil is, again, the winner, with a cold crank number of 3700. 

Nock Volatility Test

This test is performed to determine how much motor oil evaporates in warm temperatures. Redline has the least amount of weight loss when exposed to extreme heat. 

Thermo-Oxidation Engine Oil Simulation Test

This test is performed to determine the deposits that are formed in the oil when they’re exposed to high temperatures. In heat, lubricants usually form some kind of residue that will slow down the efficiency and performance of your engine. 

Especially when dealing with turbo engines, minimizing the amount of deposits in your engine is especially important to keep it performing well. Using this test, once again Amsoil has shown the least amount of weight added, making it the best product when it comes to deposits. 

But that may be getting a little more complicated than what you’re looking for. To determine which product truly works the best, you have to try it for yourself. 

What are the Difference Between Amsoil, Redline, and Royal Purple


Founded in 1979 in France, Redline is one of the leading brands of motor oil in the U.S. It’s especially well-regarded in the world of competitive racing, but general car enthusiasts have also spoken highly of the product. 

Customers have reported that their cars have never run smoother or quieter than when using Redline. The acceleration in one driver’s vehicle was almost inaudible, and the handling was never better. 

Part of the reason why has to do with the materials within Redline that help your car’s engine reduce heat temperatures as well as keep the engine running clean. Redline has superior temperature capability, making it easier to start no matter what the temperature is. 

If your engine is making a lot of noise, then it’s quite possibly related to an acid deposit that’s making the parts sluggish. But Redline’s materials will clean out deposits as it runs through, reducing the chance that your engine is going to corrode or break down. 

One of the major downsides, however, is the price. Customers have noted and complained about it being one of the more expensive oils, but few have complained about the benefits it offers. 

Royal Purple

Based out of Porter, Texas, Royal Purple has been around since 1986. Designed to be used with cars that have high mileage, the oil is made from synthetic Synerlec additive technology. This is a proprietary blend of materials that are known to help fight friction, boost oxidation and generally keep your car running healthier longer. 

Some customers have reported that Royal Purple completely revitalized their engines. When they opened their hoods, they were astonished to see barely any wear after making the switch. 

But others were less than enthusiastic. One customer even reported that after using Royal Purple his truck’s performance suffered considerably. But, again, this is the cheapest oil of the three, so quality may be lacking along with the cost. 

Another problem some customers have mentioned is the packaging, which is often prone to leaking, especially when the oil is shipped.


Amsoil is purely American. Founded in 1972, it’s one of the best known synthetic lubricants on the market. The brand made history when it became the first to meet all the standards set by the American Petroleum Institute Service.

And it’s true, you’re not going to find a better oil that cleans your engine while keeping it running smoothly. It’s also the longest lasting of the three, with oil changes much less frequent than other products. Furthermore, Amsoil contains additives that help combat rust, giving your engine a longer lifespan. 

But, once again, you’re going to get what you pay for, and in this case that means paying quite a bit. Amsoil is not cheap by any stretch of the imagination, but the advantages you’re getting in return make it well worth the cost. 

So What’s Better?

Ultimately, the question of which is the better product is going to depend on you. If you’re someone who only shops for the best, the answer will be much easier, but those concerned with budget may have a harder time committing to an expensive purchase. 

As engines continue to get more complex, so too must their accompanying oils. A good synthetic is going to prolong the life of your engine while keeping it running smoothly and also cleaning it. For our money, Amsoil is the best product out of the three, but that may not be your conclusion. 

Your conclusion will be determined by your budget and your personal preference. Royal Purple is the cheapest, and offers a lot of the same protection, though you’ll run out faster. Redline is almost equally as expensive as Amsoil, but it also doesn’t last quite as long. 


Is Amsoil better than Royal Purple?

That depends. Amsoil gives you premium performance at a much higher cost. Royal Purple has some of the same benefits, but won’t last as long. Ultimately, Amsoil is a superior product, but Royal Purple may make more sense cost-wise. 

Does Royal Purple clean the engine?

Yes, Royal Purple offers superior corrosion protection. As oil runs through your engine, it builds up deposits of acids as all lubricants do. These acids, when run through your engine, can corrode the metallic parts, eventually breaking them down. 

Royal Purple cleans out the acid deposits through a process known as advanced synthetic solvency. 

Is Redline Better Than Royal Purple?

One of the reasons Redline is superior to Royal Purple, apart from the length of time between oil changes, is that it has better temperature capability. This means Redline oil makes your engine easier to start in both colder and warmer climates. 

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