5w20 vs 5w30 – Complete Guide You´ll Ever Need [Updated]


Have you ever wondered 5w30 VS 5w20 what does mean? Putting the wrong type of motor oil into your vehicle’s engine can cause catastrophic effects.

It’s not something you want to experience! That’s why putting the right motor oil in is so important. You don’t get your money’s worth if you’re using sub-par engine oil. Trust us.

Yes, you might be one of those people who take their car to the garage when they need their oil changing. But try not to use that as an “out” for not knowing what you should be filling it with.

Imagine if you were stranded with no mechanic in sight? You won’t be able to properly fix your vehicle and you’ll be stuck for who knows how long!

Changing your car’s oil doesn’t have to be a scary thing. It’s something that every car owner will have to do at least once in their life. We are here to help you with our complete guide to 5w20 and 5w30 motor oils.

So, if you are ready, we will start by talking about viscosity.

Oil Viscosity

What’s is viscosity? Well, this is the term used to refer to a liquid’s ability to travel. The lower the viscosity, the runnier the liquid.

Maple syrup, for example, is more resistant to travel so it’s given a higher viscosity number. Makes sense, right?

What does “W” means?

You will have noticed that there is the letter “w” in both of these oils. It means winter. It’s a common misconception, so don’t panic!

The reason for this is that engine oil’s viscosity changes when under different temperatures, hence why it’s such an important factor when choosing your engine oil.

In short, the longer the oil takes to travel through your vehicle’s system, the higher the viscosity. Thus, 5w20 has a lower viscosity than 5w30.

5w20 Versus 5w30: What They Do and What They Do Not Do

To be completely honest, motor oil works the same way as grease; it minimizes the friction between surfaces or moving parts. The oil in your engine makes sure that all the complicated components inside don’t grind against each other.

Having said that, there is a lot more to it.

Motor oil, regardless of which one you choose, helps to clean your vehicle’s engine. How? Because it eliminates silicon oxide and any acids that are borne through the engine’s working life.

It is probably obvious to you now why mechanics and engineers always seem to nag you about flushing out your oil!

Eventually, there comes a time when your oil will turn a bit slushy. Yep, not a pleasant word but it’s the truth.

As you might imagine, this isn’t very healthy for your engine! It is a completely unavoidable evil though, and you can make the process slower if you look after your vehicle properly.

5w20 VS 5w30: What’s The Difference?

What´s the difference between 5w20 and 5w30? The main difference between 5w20 VS 5w30 is viscosity. We mentioned earlier that the higher the viscosity, the larger the number. Therefore, 5w20 is less viscous than 5w30 motor oil.

When 5w20 motor oil is inside your engine, it will cause less friction. This means the crankshaft, pistons, and valve train won’t have to work as hard to get the job done.

Yep, this boosts fuel economy (but only by a small amount). Plus, the runnier consistency ensures the pump can move it to the pan (and the other parts of the engine) efficiently.

If you live in a cold part of the world, you will want to opt for 5w20 motor oil.

Conversely, 5w30 has excellent heat-resisting abilities so works wonders for those of you who live in warmer climates. It is the most commonly used oil for car owners thanks to the extra protection it offers the engine.

Engine Oil Codes Explained. 5w20 VS 5w30 >> Check out the video below:

If you don’t want to think too hard about it, you should opt for 5w30 every time. Why? Because it is almost guaranteed to work with your engine, and it can deal with loads of temperatures. A perfect all-round solution if you ask us!

Have a look at the table below for a quick-glance edition of the differences between the 5w30 versus 5w20:

5w20 Motor Oil5w30 Motor Oil
Perfect for colder climatesPerfect for warmer temperatures
Let’s the oil move easily throughout the engineCan deal with a variety of temperatures
Engine components don’t have to work as hard since the oil is thinner (i.e. the viscosity is lower than 5w30)Works with many types of engines
Cheaper than 5w30Doesn’t break down when it’s put under high temperatures

Which Oil Should You Use?

By now, you might have already decided which motor oil is the best fit for you. However, if you haven’t, this section is the place to be.

Both types of oils offer a great level of protection, but before you choose which one to purchase, you need to think about the average temperature in your area.

For those of you living in a warmer climate, your best option is the 5w30 motor oil. It is a tad more expensive but it won’t fail you when it’s hot enough to fry an egg on the pavement.

For those of you living in a colder climate, you need to purchase the 5w20 engine oil. It has a lower viscosity, so it is able to heat far quicker than the aforementioned type of oil. 

So, what about all you fellows who live somewhere pretty neutral? Which path should you take? To tell you the truth, it really doesn’t matter! You can use whichever you can get your hands on.

You could even take it to your trusted mechanic who’ll be able to give you a deeper insight into which one would work the best for you and your vehicle.

What Will Happen If I Put 5w20 In Instead of 5w30?

What will happen if you put 5w20 in instead of 5w30? Honestly? Not much! You won’t have a huge engine failure and it will still protect your engine from any damage. You will be kept in pretty safe hands. They offer similar levels of safety, it’s just the viscosity that changes.

However, you might want to think about changing your oil sooner than you would if you put the “right” type inside. Otherwise, you might notice a somewhat significant drop in your miles per gallon.

Aside from that, we would say that your car will run as smoothly as ever!

Although, it does depend on what kind of vehicle you have. If you have put the wrong kind of oil in a sports car, your best option is to change it as soon as possible. Why? Because they tend to have a variable valve timing engine that will run more efficiently on the manufacturer’s recommended oil.

Is Thicker Oil Better For Older Engines?

You need to stick with what the car manufacturer has recommended. It is a common misconception that thicker oil offers more protection since it doesn’t necessarily do so. However, if you think you are having trouble, then we would suggest that you take your car in to be checked over by a qualified professional.

The thickness, or velocity, is decided based on the engine’s tolerances and can relate to the age of the engine. But, it’s important to realize that this only applies when there is a lot of wear on the inner workings or if the tolerances have become less accurate. Nine times out of ten, you need to stick with the same oil.

Thicker does not mean better. But, as we said, talk to your trusted mechanic if you are experiencing difficulties with your engine.

When Should I Use 20w50 Oil?

There are a few factors to consider when deciding whether you should use 20w50 oil. We will cover the basics here.

Firstly, it is important to note that it depends on your specific vehicle’s oil recommendations. After all, the manufacturer knows best when it comes to what to put inside their own car!

When should I use 20w50 oil? You should only be considering using 20w50 if you have one of the following types of vehicles:

  • Small diesel engine
  • Large diesel engine
  • Gasoline engine
  • Motorcycles
  • Airplanes

If you don’t, it’s not worth your time checking with the manufacturer because the answer will be “you shouldn’t use it”.

Secondly, if you’re pulling a trailer, you will probably need 20w50 oil. Why? Because activities like this put your vehicle under a lot of stress. This thicker oil can help by preventing any break down under high temperatures.

Finally, it depends on the age of your engine. Now, some people won’t agree with us as it is an arguable point. However, this oil type has been known to prevent the engine’s lifespan by offering supreme protection. 

Can You Mix Synthetic and Regular Oil?

Can you mix synthetic and regular oil? Yes, as you might have gathered by now, you can indeed mix synthetic and regular oil. Your engine won’t have a hissy fit. But, you need to make sure that you’re doing it for the right reasons.

People mix synthetic and regular oil for all sorts of reasons. Some of these are:

  • They are running low. If you are on a long journey and you’re almost out of oil, the gas station you pull up at might not have the right brand. Therefore, you don’t have much choice.
  • They want to see an increase in performance. This one is a huge myth. Mixing synthetic and regular oils does nothing to boost performance (especially if your car takes a full synthetic oil).
  • They want to extend their engine’s lifespan. Regular oil degrades faster than the synthetic variant, so mixing the two can increase this. However, it’s important to note that you’d need quite a lot of synthetic oil to make a noticeable difference.
  • They want to save money. Yep, synthetic oil is more expensive than the regular stuff so, why not?

What Are The Disadvantages of Synthetic Oil?

What are the disadvantages of synthetic oil? there are still some disadvantages to using a fully synthetic type. I have listed some below, let’s take a look at them:

  • It doesn’t hold lead in the oil suspension. This won’t apply to you if you don’t have an old car. Depending on the age of your engine, it might still need leaded gasoline to run, which would render synthetic brands useless.
  • It has different disposal methods. You need to tell your service center that your car uses synthetic motor oil because they have to deal with it differently.
  • It’s pricey. Yep, it’s more expensive than regular oil.#
  • It’s not great for all engines. Specifically, it should not be used in rotary engines.
  • It reduces friction. This can be both a negative and a positive aspect. It posed a few problems when engines needed a break-in period but that isn’t such a big deal these days.
  • It doesn’t work with racecars that use roller lifters. This is down to the aforementioned reduced friction property of synthetic oil.

Nowadays, synthetic oil is used by car manufacturers and is the number one recommended product by qualified mechanics

Can I Use 5w30 Instead of 5w20 In my Ford?

Can I use 5w30 instead of 5w20 in my Ford? In short, yes. Ford indeed changed their recommendations from 5w30 to 5w20 because of fuel economy.

However, you can still use 5w30 in your Ford vehicle. Nothing untoward will happen. In fact, many garages only use 5w30 when changing oil in their cars.

Having said this, you need to consider your car’s warranty. If you are still under warranty with Ford, using a non-recommended motor oil (in other words, 5w30) may void your agreement.

So, we suggest that you stick to 5w20 while you are under warranty.

Does Oil Type Affect Gas Mileage or MPG?

Over recent years, vehicle manufacturers have started to reduce their recommended oil viscosity since they believe it will improve fuel mileage. To be honest, it might all before nothing. Why? Because there is hardly a difference between the gas mileage in synthetic and conventional oil types.

Does Oil Type Affect Gas mileage or MPG? No, as of yet, no one has managed to find any consistent change in fuel economy at standard temperatures between conventional, semi-synthetic, and full synthetic motor oils.

You won’t notice any change in the driving experience if you switch out the oil.

The only way to measure it would be under strict lab conditions.

Which Oil Is Best for Mustang?

The viscosity Ford decided to go with for their Mustang is based on a standard running temperature of roughly 210 degrees Fahrenheit. Why is this important? Oil thins to its optimum viscosity when the operating temperature is emitted. This is why the majority of the wear and tear on your engine will happen at startup.

Which oil is best for Mustang? The specific oil you need for your Mustang depends on the model you purchased. We’ll take a look at the recommendations by year below but for specifics, check your manual:

  • 2018 Mustangs — 5w30, 5w20, 5w50
  • 2017-2015 — 5w20, 5w30, 5w50
  • 2014-2010 — 5w30, 5w50
  • 2004-1999 — 10w30

Frequently Asked Questions

Here are a few common questions people often have about 5w20 versus 5w30 oils:

The Bottom Line

Regardless of the temperature, both of the oils will work to keep your engine safe. However, we know that you are probably still worried about it! Here’s our opinion.

Choose 5w30 motor oil! Why? It is very hardy and has a high film that can withstand extreme climates, so no matter where you go, you and your vehicle are protected.

Plus, this kind of oil works with almost any engine type! It’s a no brainer for those who aren’t so clued up on the inner workings of their car.

If you’ve had enough oil talk for one day, we’ll see you soon. But if you are seriously interested in becoming the go-to friend for motor oil problems, you’ll want to take a look at our “things to remember” list below:

  • The higher the viscosity, the higher the number
  • The “w” stands for “winter” not “weight”
  • Motor oil doesn’t just keep parts from grinding, it also cleans the engine
  • 5w20 offers less friction and is great for those living in colder regions
  • 5w20 heats quicker
  • 5w30 works in almost all engine types and won’t break down in hot climates
  • For neutral regions, pick either, but we recommend 5w30
  • Both provide a decent level of protection

Recommended Reading

For more helpful articles about RVing please check out our articles below:

Can You Pull a Boat Behind a Pop up Camper? All Facts You Need

Does RV Insurance Cover Water Damage? What You Need To Know

What Does Solar Ready or Prep on A Camper Mean?

How to Easily Determine the Correct Wheel Covers for RV Tires (17 Examples)

Mike Gilmour

Hi, I'm Mike, co-founder, and editor of RV and Playa. My passion is traveling (with my RV) and enjoying the day at the beach (Playa)! Well, I originally created this blog as a way to share what I've learned by experimenting with the RV lifestyle, and I want to help others develop in life through new skills and opportunities.

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