Can You Mix Oil Brands?

So you are debating mixing oil brands to save a few extra dollars? You may be surprised by the answer. This is a common question asked by people just getting started with their cars. The big question many ask is if mixing brands of oil will harm them or their engine. It really depends on the type of oil you’re using and the type of vehicle you have as well. So in this guide, we’ll cover everything you need to know about mixing oil brands, whether it’s good or bad and why.

Mixing oil brands might sound crazy, but some car owners prefer to mix brands. Homeowners often use a combination of mineral and synthetic oils in their furnaces in the winter. But is it okay to mix oil brands in your car?

Can You Mix Oil Brands?

Yes, you can mix oil brands, but experts do not advise doing so. If you choose to mix oil with the same weight and viscosity that is recommended in your vehicle owner’s manual oil will not hurt the car’s engine.

So, why isn’t there a definite answer to this?

Oil companies all have their own additives that they put into the oil to help with fuel economy, emissions, and engine protection. This oil additive will be different if you’re using a different brand of oil. When these additives combine with the other company’s additives, they don’t form a good mixture and could lead to your engine’s performance decreasing over time.

So, you CAN mix oil brands if you really want to—but we wouldn’t recommend it. A better option is to stick with one brand of oil and stick with it as long as possible.

Is It Bad To Mix Oil Brands?

Yes, it’s bad to mix oil brands. However, one can still choose to do so even after knowing the consequences.

One thing that’s important to keep in mind is that the type of oil you choose will depend on the type of engine you have in your car. For example, many new cars use synthetic oils now, because they are designed to be more durable and combat high temperatures. But older cars might not be able to handle synthetic oils, which contain more additives than traditional oils do. So if your car is older than 10 years, you should probably stick with traditional motor oil instead.

The most important thing is to make sure you never mix oils from different brands. This can cause problems with your engine, and could even lead to serious problems like burning out your engine altogether. To protect yourself from this kind of trouble, always make sure you’re using oil from the same brand.

What Happens If You Mix Different Brands Of Motor Oil?

What happens if one mixes different brands of motor oil depends on whether one has the perfect mix or not. However, experiments can help figure out the answer.

It’s a question that comes up every once in a while: what happens if you mix two different brands of motor oil?

Well, to answer that question, here’s one sample experiment. The experiment had three bottles of motor oil on hand: Shell, Pennzoil, and Motorcraft. Experiment participants took them into the lab, put them each in separate beakers, and carefully poured one drop of each brand into a third beaker.

Then they waited. And waited. And waited some more.

After almost nine hours, the Motorcraft and Shell oil had settled into their own layers in the beaker—the Pennzoil hadn’t settled yet. After another four hours, it finally did settle: all three brands were completely separated from one another in their own clear layers at the bottom of the beaker!

So, why does this happen? According to experts (and in science textbooks), this is because oil molecules are very big and heavy compared to water molecules—so they sink to the bottom under their own weight!

Can You Mix 2 Brands Of 2 Stroke Oil?

Yes, one can mix 2 brands of 2 stroke oil. However, one might want to consider getting advice from a mechanic before doing so and to check oil viscosity for both brands.

Some people who use 2-stroke engines are afraid that if they use a different brand of oil than what their engine is made for, it will cause damage to the engine. This isn’t true!

2-stroke engines are designed to work with a certain octane level, but the actual oil doesn’t matter. What matters is that you’re using enough oil in your engine.

If you’re not sure what kind of oil your 2-stroke needs, ask your mechanic. If he says it’s okay to mix brands, you can keep using the same kinds of oil.

Can You Mix 2 Different Brands Of Synthetic Oil?

Yes, one can mix 2 different synthetic oil brands if they have the same weight and viscosity. However, experts do not recommend doing so.

Mixing synthetic oil brands is usually not a good idea. First of all, synthetic oil is made in a very precise way. The base stock is distilled and treated to exact specifications with additives that are also carefully controlled. Mixing the two brands may ruin some of the synergistic qualities of both oils, or at least reduce them significantly.

Different motor oils have different viscosities. The viscosity (the thickness) of an oil is important because your engine needs the right amount of lubrication at each temperature range. Your car’s computer recognizes which brand is being used (because they have different chemical signatures) and it opens or closes vents inside your engine to keep it running at its best.

Is It Ok To Mix Different Oil Viscosity?

No, it’s not ok to mix different oil viscosity. If one decided to mix different oil viscosity, there would be several considerations to keep in mind.

Mixing different motor oil viscosities is a bad idea. Motor oil is not like salad dressing: It can’t be shaken together to blend it, and it’s not like paint, where you can add the same color over and over again. The end result of mixing oil types is a mucky, gritty sludge that will clog your engine’s filters.

So why do it? Because you can save money! If you have some 5W-30 in your garage and run out, you can get another quart of 5W-30 at the corner store and call it good. Or so you think! Changing the type of oil in your car isn’t as simple as just going to the store and picking up a replacement; a lot more goes into that decision.

And if you want to know what kind of oil your car needs, don’t trust the label on the bottle—it’s only an estimate, and it could be way off. Your best bet is to check with your local shop or use one of those handy motor oil viscosity lookup tools.

Can I Use 4-Stroke Oil In A 2-Stroke Engine?

No, one cannot use 4-stroke oil in a 2-stroke engine. However, there might be some considerations for it.

This is a question we hear every day.

First of all, the two types of oil have different viscosities, which means they’re not going to mix and stay together. And I don’t need to tell you what happens when you try to run a motor with two different kinds of oil.

What you want is called 2-stroke oil. It’s specially designed for 2-stroke engines and will do what it needs to do without any trouble. You can find it at any gas station or bike shop, just look for the green label.

There could be some considerations around this. It depends on what kind of 2-stroke engine you have, how old the engine is, and the type of 4-stroke oil you’re using.

Can You Mix Different Brands Of Oil With The Same Weight?

Yes, one can mix different brands of oil with the same weight. However, there are some considerations to follow when doing so.

The difference between 10W-30 and 5W-30 is really pretty negligible—the real difference comes from the manufacturer. So if one brand makes a 10W-30 that works perfectly for your car but the other brand makes only a 5W-30, don’t just assume that it’ll be fine to switch! Just because they’re both 5W-30 doesn’t mean they have the same weight or formula!

Now with that said, there’s one thing you DON’T want to do: You DON’T want to use two different brands of oil with different weights in the same vehicle. Different manufacturers may use different weights for their oils, which can cause problems in your engine if they aren’t compatible.

What Happens If You Mix Synthetic Oil With Regular Oil?

If one mixes synthetic oil with regular oil, there would be some problems with the engine. However, by following appropriate mixing proportions one can avoid such problems.

Let’s say you have a car that needs synthetic motor oil. Your car owner’s manual tells you to use synthetic oil in your engine because it lasts longer than regular oil. You go out and buy the recommended synthetic oil for your car, but then you’re driving on the highway and all of a sudden, your car starts making a weird noise, like a purr. You pull over and check under the hood—the engine is covered in black smoke!

The smoke is coming from the motor oil in your engine! The synthetic motor oil is mixed with the regular motor oil and creates enough friction to melt into black soot. If you want to use synthetic motor oil in your car, use only a small amount of regular motor oil to mix with the synthetic motor oil. Or just stick to using 100% synthetic motor oil; it’ll last longer that way.

Can You Mix Synthetic And Conventional Oil?

Yes, one can mix synthetic and conventional oil. However, one would not want the results. For a clean-running vehicle, only use conventional with conventional.

The two oils have different chemical compositions. The molecules are smaller in conventional motor oil, so they can make their way into more places in your engine. However, that makes it less stable than synthetic oil, which is a much larger molecule. In fact, synthetic oil can suffer from evaporation due to exposure to air.

Conventional motor oil is actually easier for your engine to process, because of its smaller size; the smaller the molecule size, the more efficient your engine will be at breaking down the fuel and converting it into power. Just keep in mind that when you mix synthetic and conventional motor oils in your car, too many of the small molecules could cause issues in your engine, while too many large molecules could mean that your engine doesn’t get enough lubrication.

In short: if you want a clean-running vehicle and you want it fast, go with synthetic oil or use a combination of both synthetic and conventional oils.

Can You Mix 5w30 And 10w40?

Yes, one can mix 5w30 and 10w40. However, experts don’t advise doing so because of potential problems.

The reason for this is that the viscosity, or thickness, of the oil in the engine depends on a number of factors: engine size, engine power, driving conditions, etc. And mixing oil types can cause problems like increased wear and tear on your engine. So even if it seems ok at first, chances are good that you’ll end up with serious damage down the road.

And we don’t want that for you! We want you to have a smooth ride and avoid any major automotive catastrophes.

So if you want to make sure things stay safe and smooth in your car: stick with one type of oil until your next oil change.

Can You Mix 5w-30 And 5w40 Oil?

Yes, one can mix 5w-30 and 5w40 oil. The American Petroleum Institute (API) says it’s okay to use the two kinds of motor oil in any proportion. However, doing such may not be very ideal for all cases.

It’s true that 5w-30 and 5w-40 are different weights of motor oil. Just know that weight refers to how thick the oil is. The lower the number, the thicker it is; the higher the number, the thinner it is. Both 5w-30 and 5w-40 are thick oils—they just have different thicknesses.

But that doesn’t mean it’s a bad idea to mix them together. All API says is that if you do mix them together, they both need to be API-compliant, which they both are. So while it might not be ideal, it won’t hurt your car if you use 5w-30 and 5w-40 motor oil in any combination that you want.

Can You Mix Diesel Oil Brands?

No, one cannot mix diesel oil brands. Doing so is a bad idea. However, if one has to mix oil brands due to certain circumstances, there are considerations to keep in mind.

The parts of an engine that come in contact with the oil are engineered by the manufacturer to work optimally with a specific brand of oil. If you put in a different brand, there’s a chance that it won’t reach the right temperature and will just sit there getting all gross. If this happens enough times, your engine will basically start to self-destruct.

So, what if you change brands every time you fill up and don’t always drive long distances? Can you mix and match brands then?

Nope! Even if you drive short distances with frequent oil changes, your engine can still get confused by the different viscosities of oil. And those viscosities are chosen specifically to make sure your engine runs as smoothly as possible at all times. In fact, your car might run just fine for a while if you switch brands, but it could develop problems later on like stalling or rough idling.

And that’s not even talking about older cars without sensors that tell the car what kind of oil is in it!

Can You Put 2 Different Types Of Oil In A Car?

Yes, one can put 2 different types of oil in a car. However, experts say that mixing different oils is not a good idea.

Some car owners try to put a different type of motor oil in their car than the manufacturer recommends, and it’s not always a good idea! Let’s start with some background:

In your engine, motor oil is used to make sure that your moving parts are well-lubricated and protected from friction. It also keeps them at a constant temperature so that they can operate efficiently. Motor oil is measured by viscosity—how thick it is at room temperature—and by its performance in terms of protection against wear and tear.

Too much friction can cause serious damage to your engine, which is why it’s important to use the proper kind of oil!

Can You Mix Long-Life Oil?

Yes, one can mix long-life oil with standard oil. However, doing such may not be a great idea.

Long-life engines aren’t meant for constant high-performance driving. Because of that, they shouldn’t be driven as regularly as a standard engine.

So what exactly does that mean?

Long-life engines require a break-in period before they’re ready for regular driving conditions. That means you have to put in some time driving around town at slow speeds, gradually increasing your highway speed until you can hit the maximum posted limit.

When you’re not doing this, you should keep your long-life engine out of situations that would cause it to overheat or run hot (such as stop-and-go traffic).


When most of us think of changing oil, we assume that there is a specific formula to follow. This can actually be a problem for those of us who love saving money. The truth is that you can mix motor oil brands, but it is not recommended that you do so often. Mixing two different brands in your engine will eventually cause damage and the effects may not show up for a while, which means that you could destroy your engine without even knowing it.

Robert Aksamit

Robert Aksamit

Robert Aksamit is a mechanical engineer and automotive industry expert. Robert was born in Minnesota and worked in the US automotive industry for 25 years. He is highly regarded for his passion and dedication to continually improving vehicles in response to customer feedback. Robert has a keen eye for sourcing the best vehicle components and materials on the market and is always looking for ways to enhance the user experience. As a writer, Robert covers automotive-related topics. Read more on Robert Aksamit's about page. Contact Robert:

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