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3 Reasons To Quit Asking What Oil To Use In Your Car

If you have ever wanted to know about what engine oil you should use in your car, grab a pen and pad.


It seems, by far, the number one question I get from people who know me and my background is, what engine oil should I use in my car.

Before I dive into the complex oil industry, you need to know a few things about me. For the past 15 years, I have been inside the automotive industry, learning, fixing, and teaching all things about automotive.

During this time, I spent over two years dedicating my studies to engine oil. I am about to tell you that my research is based on a thorough understanding of the subject.

I understand how confusing it can be as a consumer and blasted with confusing marketing. There are dozens of brands competing heavily for your business. On top of that, you have self-proclaimed "car guys" who think they know about oil; most have no clue. Then finally, you have the auto store "pros" who are also basically clueless.

In all reality, just about anyone you talk to about engine oil will tell you what they have been marketed into believing. It is quite sad. How are you, the consumer, ever supposed to know what to get for your car?

Luckily there are ways you can learn and not spend two years doing it. Read my three reasons why you should stop asking about what oil to use in your car, and you should know enough at that point to make a well-informed decision.

Reason 1: Read The Owners Manual
Ever wonder what that strange thick book is that comes with your car? Well, believe it or not, that is the manual on how to use your vehicle. Included inside is an entire section on what the manufacturer has specified is the correct oil to use.

In the manual, there is an image like the one shown here. It is called the API Donut. This image shows you everything you need to know about oil's viscosity and the rating that your car needs according to the standard in the year [Honda, Toyota, GM, Ford, etc.] built it.

American Petroleum Institute service rating

For example, if I drive a 2011 Honda Odyssey, my API donut would tell me that I need 0w20 Energy conserving engine oil with an American Petroleum Institue Rating (API Rating) of SN.

The API rating is what you need to pay attention to. Oil service ratings are forward compatible. That means if you are driving a 2008 car with a service rating of SM, the current standard of oil SN will work in your vehicle.

Take a look at this chart below to learn more about what oil was the standard in your year. The main thing here is that you know the viscosity and proper API Rating for your vehicle.

API Service Index Chart By Year

Keep reading, and you will find out why it does not matter what oil you get as long as you know those two things.

Reason 2: Do Your Own Research
No one has ever truly understood something by just hearing it from another person. Many have told you to use Mobil 1, or Castrol, or Valvoline, or Royal Purple by this same fault. While their experience with these oils is good, it begs the question, why did they recommend it?

Honestly, has any one of those people ever taken the time to have each of those oils evaluated by a lab? Have they sent in samples to have them tested for breakdown over the lifetime of the oil? Probably not, that is work, and they would not understand the spec sheet anyway.

If someone tells you to buy a specific oil brand, take that with a grain of salt, or probably a salt block. Most people only buy what they hear their family/friends suggest or what marketing on the bottle stands out the most.

If you want to know what oil you should buy, do yourself a favor and visit the rabbit hole, I went down to figure it out.
It took a lot of time, but now I know for myself what oil I want to use and how it saves me money.

You will not only become fully aware of what you need for your car, but you will also learn (as I did) how full of it most people are when they talk about oil. Has it ever hurt you to learn how to save money and take better care of your car? I doubt it.

Reason 3: Not All Oil Is Created Equal
This section is probably the most important next to the first. Know why oils are different is key to learning why your neighbor sounds like an idiot.

To fully understand why oils are different, you first need to know how they are created. Every oil you get (I do not care what it is) starts with a base stock. The base stock oil is incredibly important to how well the oil will perform over time.

Base stocks get categorized into groups. Group I, II, III, IV, and V. If you want to know more about these base stocks and what they mean, Google "engine oil base stock." Once you do that, good luck; you probably will not stop reading.

You will find out all sorts of incredible data about mineral vs. synthetic, motor oil additives, and everything in between. To steer you in the right direction without depriving you of the learning opportunity, I would suggest starting out learning those two things.

Next, you are going to start reading about additives. I like to think of these as the "trade secret" of every motor oil manufacturer. Additives are what these companies are selling you, but you did not know it.

For this example, we will use Castrol. (FYI, I have ZERO ties to Castrol, I am using them for this example because they market well.) This company has come a long way in marketing their product. Their GTX Ultraclean claims sludge protection; the GTX Magnatec claims wear protection and sludge protection. Then Castrol Edge claims increased engine performance, wear protection, and sludge protection. Last you have the Castrol Edge Extended Drain that claims longer drain intervals, engine performance, wear protection, and of course, sludge protection.

Castrol Engine Oil Bottles

Castrol, like everyone else, is then marketing those additives in a way that sounds fancy. How cool does fluid titanium sound? I would buy it if I knew nothing about engine oil because it makes me feel like I am protecting my car.

Sadly, I would say that 90% or more people on the road today and the quick lube places they visit all know about the same information as you, the consumer.

So what do all these additives mean for you? Excellent question. They mean that depending on what you buy, you will either get a chocolate cake or maybe an ice cream cake, but you will get a cake. All oil starts as a base, but then through a proprietary blend of additives with fancy names, they make their oil do something different than a competitor.

For instance, the "superior wear protection" that Castrol touts is nothing more than anti-wear agents and friction modifiers. They can claim better wear protection over a competitor if they have more of this additive. So that 10x better performance tells you they have found a way to blend in the most robust anti-wear agents to achieve the desired result.

Engine Oil Additives

They are not telling you that they could be lacking in other areas, though. Oil companies are not going to tell you what they suck at but only what they do well. Then they market it on their bottles, so that is all you see.

Furthermore, ten times better than who or what? The latest industry standard is the who and what. I am not going down that rabbit hole now, so have fun and let me know what you find. But I can tell you this; the industry has changed multiple times over the past 20 years. Food for thought.

If you take only one thing from this article, remember this. Engine oil is a continually evolving science. Oil companies are targeting you with fancy terms to get you to buy their oil. The owner's manual in your car will tell you precisely what you need, but you may be purchasing the latest standard that exceeds what is in your book.

Quit listening to people who do not know what they are talking about; they probably have no clue either. Do your research and learn for yourself what you should buy. Not only will you learn something, but you will also remember the information better.

I can tell you that I use a synthetic oil filter and API SN rated engine oil for my car, which happens to be a Toyota Prius, a Honda Odyssey, and an overbuilt 1994 Toyota 4Runner with a 2JZ-GTE bi-turbo.

I will also tell you that I spend less than $35 per vehicle for the most premium oil change you cannot get at any fast lube place. I am saving money and giving my car what it needs rather than what I think it needs. I also buy what is on sale and rotate through different brands periodically to expose my engine to various additives.

As long as you know the viscosity rating and the API service rating, it doesn't really matter what brand you use for most cars. There are some BMW and Mercedes out there you need to pay attention to, but again, read the manual, and it will tell you what you need.

If you still have questions or want to talk more about engine oil, feel free to find me on Facebook or Twitter. I am happy to answer oil questions, but please do not ask me what brand to use because I will refer you right back to here.

Talk to me about base stock, additives, supplements, or filtration, and I am glad to help you understand. I hope your week has been fantastic and I look forward to seeing you in the next article.

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Peter Neilson is an automotive consultant specializing in electric cars and hybrid battery technologies. He holds a Bachelor of Science in Automotive Service Technology from Weber State University. Peter can be reached on Linkedin and you can tweet him at The_hybrid_guy on Twitter. Find his page on Facebook at Certified Auto Consulting. Read more of Peter's stories at Toyota news coverage on Torque News. Search Toyota Prius Torque News for more in depth Prius coverage from our reporters.


Arcee (not verified)    November 21, 2020 - 11:28PM

Simply use what is indicated in the owners manual. Doesn't matter what brand or even type (conventional, synthetic blend, synthetic) at that point. Any oil that matches what the manual says will be perfectly fine.

My GM vehicle calls for dexos 5w30. I simply buy whatever full synthetic, dexos licensed 5w30 oil I can get at the cheapest price. Don't care what brand as long as it is dexos licensed. When the oil life monitor says to change the oil, I repeat the process. I also don't overthink filters. I just buy the ACDelco filter listed in the manual.

ks (not verified)    April 22, 2023 - 12:30AM

Your right, it's nearly impossible to differentiate between brand characteristics from what is published, but where is a consumer to get objective data needed to make an informed choice? Which oil is better for long trips at Interstate speeds in hot weather? Which allows longer change intervals when driven infrequently and for short distances? And how is one to know if 10,000mi. change intervals with, say, 0W16 in a hybrid truly is okay - available consumer tests measure wear metals, viscosity, and TBN, but how can a consumer determine when an oil has aged to the point of depositing on piston rings?

dh (not verified)    June 2, 2023 - 7:45PM

In reply to by ks (not verified)

Think about this, the auto manufacturers spend hundreds of thousands of dollars, possibly millions to find the best oil for your engine. The oil that is recommended is the best for all conditions, all driving habits, all climates, period. This is the point of the article, the manufacturers know what is best, follow their recommendation and you'll be okay. The argument about making a more informed choice is misguided, the best information is already there you just have to believe it, even if it doesn't come with made up buzz words like the label on the bottle $15/qt oil.

Mark (not verified)    July 14, 2023 - 8:53AM

Interesting commentary from an electric vehicle/battery specialist.
I have worked in the Heavy Duty segment for 40+ years,but we are talking oils,namely automotive oils. Einstein said" if you cannot explain it simply you do not understand it yourself ".
Personal experience-I run Valvoline Maxlife,and took a 2002 Monte Carlo 3 8 to 469k miles.I only stopped there because the transmission failed for the second time(engine still ran).I also took a 2003 Monte Carlo to 303k miles on the same oil,and I am still driving it to this hypothetical here, actual experience...