Can I Use 5w30 Instead Of 5w20? [yes, but beware…]

Motor oil is essential for keeping your vehicle running smoothly. Motor oil is the lifeblood of your engine, protecting it from wear and tear. It keeps your engine lubricated, which prevents metal-to-metal contact and reduces friction. It also helps to cool the engine by absorbing heat and reducing pressure on the piston rings.  In this guide, we compare the pros and cons of 5w30 and 5w20 oil and show you how to get the most out of your motor oil.

So, can I use 5w30 instead of 5w20? No, you cannot use 5w30 oil instead of 5w20 if your vehicle manufacturer has specified to use only 5w20 motor oil in its manual. On the other hand, if a different viscosity oil is recommended for “hot climate, extended duty” in the vehicle’s manual, you can use 5w30 oil instead of 5w20 in that case. If no alternative to 5w20 is listed, using a different grade of oil may void the powertrain warranty of your vehicle.

The difference between the 5w20 and 5w30 is that 5w20 oil is thinner than 5w30.  Although 5w30 oil is thicker and can provide more protection against friction at higher temperatures, if your vehicle manufacturer has strictly specified engine oil specifications, you should follow the rules.  

A 5w30 will be too thick at operating temperature for the design intent of the engine.  I would not recommend using 5w30 instead of 5w20 if your vehicle’s manual recommends using 5w20.

If you do not use oil that meets the defined specification and viscosity grade, it could result in:

  • Component damage that your vehicle warranty does not cover.
  • Longer engine cranking periods.
  • Increased emission levels.
  • Reduced vehicle performance.
  • Reduced fuel economy.

You can check my guide on the best 5w30 and 5w20 motor oils.

In Which Condition I Can Use 5w30 Instead Of 5w20?

You can use 5w30 oil instead of 5w20 motor oil if you are driving the vehicle in hot climates, and your vehicle has covered over 120,000 miles.  As the vehicle runs, the clearances between engine parts, such as between piston and engine cylinder, and between shaft and bearings increase.  In such conditions, you would need motor oil, such as 5w30, having higher viscosity to provide better protection to engine parts and reduce leaks through clearances.

There is an SAE viscosity chart on which the temperature range of particular motor oil is defined.  From that chart, you can decide that if the ambient temperature is greater than the recommended temperature range of 5w20, you can use 5w30 oil.

Also, as technology advances, so do the tolerances in engine components.  This has led to engine manufacturers recommending 5w20 oil over 5w30 oil in modern engines as the tolerances are tighter, and they don’t require high viscosity oils unless their engines are running in a hot environment.

In the picture below, you can see that with the modern advancements in the engine i.e. efficiency and tolerances, vehicle manufacturers are moving towards using low viscosity grade oils.

vehicles are using low viscosity oils with the passing of years
https://www.infineuminsight.com/en-gb/articles/lubricant-trends/moving-to-even-lower-viscosities/

In another picture below, you can see that Honda has also shifted from high viscosity grade oils to low viscosity grade oils for its vehicle models over the years.

Hona engine oil guide
https://www.wildehonda.com/honda-engine-oil-synthetic-vs-regular/

What Does SAE 5w30 and 5w20 Mean?

This is the standard rating of automotive lubricants designated by SAE. SAE stands for Society of Automotive Engineers. The higher the number the thicker the oil. In 5w20 and 5w30, ‘w’ stands for cold viscosity grade of motor oil at 32 degrees Fahrenheit. This is the viscosity of the oil when it is first poured into the engine and the engine is not running.

The higher the viscosity of the oil, the more protection it will provide against wear.

So, the cold viscosity grade of 5w30 and 5w20 is the same i.e. 5. The lower this number, the thinner the oil and the better the motor oil’s performance at the colder temperature.

To understand the difference between multigrade and monograde motor oil, you can read my guide on SAE30 vs 10w30.

The number after the ‘w’ indicates the hot viscosity grade of motor oil. It is measured at a temperature of 212 Fahrenheit. For 5w20 and 5w30 motor oil, the viscosity grade at warmer temperatures is 20 and 30 respectively. The higher this number, the thicker the oil and the better the motor oil’s performance at the warmer temperature.

Is 5w20 Oil Synthetic?

It depends on the brand.  The 5w20 oils are either available as fully synthetic motor oil, or as a synthetic blend oil, also called semi-synthetic. 5w20 synthetic oil is formulated by a combination of refined hydrocarbons and additives. The refined products are engineered to be more uniform and consistent so that your vehicle’s engine operates efficiently with the severe changes in the climate. This is because synthetics have a more stable viscosity than conventional oils.

Synthetic blend type of 5w20 motor oil is a mixture of synthetic and conventional base oils (refined hydrocarbons). They do not contain additives. In short, they are a low-cost version of fully synthetic motor oils. They protect better and last longer than conventional oil.

Since Modern synthetic blend and synthetic engine oil isn’t going to break down with heat and age like conventional oil. This is why thinner oil like 5w20 can lubricate and tolerate heat better than the old thicker conventional oil.

5w30 vs 5w20 Difference 

5w20 is a lightweight oil that is designed to work with newer engines having tight tolerances and high efficiency. Both 5w30 and 5w20 are synthetic motor oils and have the same viscosity if the engine is operating at colder and freezing temperatures. However, for warmer temperatures, 5w20 oil tends to be thinner compared to 5w30 as the viscosity grade of 5w20 for warmer temperatures is lesser than that of 5w30 oil.

Now, let’s consider the major differences between 5w30 and 5w20 engine oil in terms of different aspects.

Operating Temperatures

The operating temperature range of 5w20 motor oil is from -35 degrees Celsius to 25 degrees Celsius, while the temperature range of 5w30 motor oil is from -35 degrees Celsius to 35 degrees Celsius.

At higher temperatures, 5w30 oil does not break easily. Due to this reason, in tropical climates, where the ambient temperature is around 40 degrees Celsius, you can use 5w30 oil. Also, 5w30 oil tends to seal better compared to 5w20 oil at higher temperatures. This helps in providing better protection to the engine components and hence prolongs the life of the engine.

The higher the viscosity of motor oil, the thicker the oil film between engine parts. As a result, it will be more resistant at a higher temperature.

Although the viscosity of the 5w30 motor oil will cause less wear and tear, and allow for smoother movement around your engine parts, it can also have a negative impact on your vehicle’s engine power, which it can cause slightly lower fuel economy. This is because your vehicle will have to do more work against the drag offered by the thicker 5w30 motor oil.

The difference between 5w30 and 5w20 motor oils is small, and switching from one grade to another should have little effect on fuel economy. Over time, you can accumulate fuel savings.

5w30 vs 5w20 for High Mileage

In several forums, people say that the use of 5W20 supposedly allows for a slight increase in mpg (miles per gallon), in addition to quicker oil flow on cold startup.  When a lesser amount of oil is in between the moving details of your motor, it will provide better performance due to low friction. As a result, the application of low viscosity engine oil leads to enhanced fuel efficiency.

Using 5w20 oil increases fuel mileage. But, if your vehicle is quite old and has covered over 120,000, 5w30 motor oil will be better. 5w30 will prevent older vehicles from engine wear due to grinding gears. Also, switching from 5w20 to 5w30 oil for high mileage older vehicles will result in lesser oil consumption.

Can You Mix 5w20 and 5w30 Motor Oils?

Yes, you can’t mix 5w20 and 5w30 if they are from the same oil manufacturer, and have the same API (American Petroleum Institute) service level with almost the same formulation. The 5w20 oil is a lighter oil while 5w30 oil is a heavier oil. Also, the resultant viscosity should be within the range recommended by the OEM. You can’t mix synthetic and semi-synthetic oils as they have different compositions and additives.

Can I Use 5w30 oil instead of 5w20 in Ford 150?

It depends on the model of Ford 150. For instance, in the owner’s manual of Ford 150 3.5L, 5w20 synthetic blend motor oil is specified. On the other hand, in the owner’s manual of Ford 150 3.5L Ecoboost, 5W-30 synthetic blend motor oil is specified. Moreover, till 2020 models of Ford 150 5. 0L, the recommended motor oil is 5w20. From 2021, 5w30 motor oil is recommended for Ford 150 5. 0L.

Wrapping Up

So, can I use 5w30 instead of 5w20? I would suggest you use 5w30 only for older vehicles that have crossed over 75,000 miles. For newer models, automobile companies are preferring 5w20 motor oil, especially for USA models to meet the requirements of CAFE (Corporate Average Fuel Economy) standards. 

I would suggest you strictly follow the vehicle’s owner manual for selecting the right motor oil as the engineers have selected an optimum oil grade based upon the tolerances, oil passages in engines, and valve timing mechanism.