SAE 30 vs 5W-30: Which To Use in Your Lawn Mower

So I guess you wondering which way to go on oil selection right, SAE 30 or 5W-30? Well, it’s a fair question, so let me help break it down for you and give you the insider on SAE 30 vs 5W-30. Then you can top up your lawn mower with confidence and get back to work. 

SAE 30 vs 5W-30 for Lawnmowers

Lawnmower engines cannot function if they lack an oil supply to keep them running smoothly and prevent them from blowing white smoke throughout your yard. But they do not run on normal oil that you find at your local hardware store. You have to ensure that the oil you are pouring into your lawnmower engine will ensure that the engine runs smoothly and produces sufficient power to cut the whole lawn. 

Thus, this article will discuss the benefits and considerations of using SAE 30 vs. 5W-30 for lawnmowers.

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Is SAE 30 the Same As 5W-30?

In terms of viscosity, SAE 30 and 5W-30 are the same but serve different functions. 

First, it will probably help to understand the terminology before anything else. The initialism SAE stands for the Society of Automotive Engineers. Founded in 1905 by Henry Ford and Andrew Ricker, the organization designed a coding system to determine the oil’s thickness — or viscosity — so people know which oil to use for each engine type.

Determining the oil’s viscosity allows one to know how long it will take to flow through the engine at zero degrees Fahrenheit. If the oil has a higher consistency, it will need a longer time to flow through the engine at that temperature.  

Contrary to popular belief, the “W” does not stand for “weight,” it actually means “winter.” The oil has a lower chance of thickening when the temperature begins to drop if the number to the left of the “W” is lower. In areas that annually experience freezing temperatures, 0W or 05 are the most common kinds of motor oil used. The numbers following the “W” are used to determine the oil’s viscosity when using it at a temperature of 212 degrees Fahrenheit. 

SAE 30 and 5W-30 have the same viscosity rating of 30 while hot, but their cold ratings differ. Drivers most commonly use SAE 30 in powering small engines, while primarily using 5W-30 in the automotive industry because it can function in freezing temperatures. 

You use the other two numbers after the “W” to display how quick thinning happens in the oil when using it at hot temperatures. Continuing the example, the 10W-30 and 10W-40 varieties work similarly in lower temperatures. However, the former has a faster rate of thinning compared to the latter when temperatures increase.

SAE 30 Oil and Its Benefits

Drivers operating small engines prefer SAE 30 because it is a single-grade oil. Since snow makes pushing a lawnmower around difficult, people are often cutting their lawns during the warmer months of the year. However, if you decide to clear away the snow because you are determined to be the first person of the new year to cut your lawn, a snowblower would require a multi-grade oil to be effective. 

SAE 30 is a non-detergent oil that gathers specific contaminants that can damage your engine. Contaminates stick to the open cracks and sidewalls, causing damage to the bearing surfaces. It also helps stabilize the oil and prevents it from thinning after exposure to higher temperatures. Oil additives work to maintain the lubricative function across a broader temperature spectrum.  

Single-grade oils such as SAE 30 are also cheaper than multi-grade ones. If you know you have multiple lawn projects and thus need a significant amount of oil, the SAE 30 makes the most financial sense. 

5W-30 Oil and Its Benefits

5W-30 is a multi-grade oil that carries two ratings. The number 5 represents its rating at low temperatures, and the number 30 is its rating during extreme heat. Five is a low number, meaning it functions well in freezing temperatures. This oil is essential in maintaining the functions of cars, airplanes, snowplows, and other engines that have to operate during the winter months.

Unlike SAE 30, 5W-30 oil possesses additives such as detergents, corrosion preventers, and other chemicals that break down sludge, prevent rust, and contribute to longer engine life. Oils with these additives are designed to keep your engine running smoothly and clean. 

When using or adjusting additives in the oil, make sure the mix is appropriate. Having too much of an additive might negatively impact the engine’s performance.

Can I Use 5W-30 Instead of SAE 30 in My Lawn Mower?

Using a multi-grade oil instead of a single-grade one is not advised. There is no reason or circumstance that you would need to use multi-grade oil unless it were a landscaping emergency in the wintertime, and you are more lenient with what happens to the lawnmower in the process. 

The only thing 5W-30 would do is protect it from freezing, but it would get cold fast due to the additives wreaking havoc on the engine.

Will Using 5W-30 Damage My Lawn Mower?

The oil you put inside your lawnmower engine functions in the same way as the oil in your vehicle does. Once you start the engine, the oil prevents the pistons from grinding against the walls of the cylinder by lubricating them. 

Then, the internal heat from the engine gets transferred to the cylinder block and out of the exhaust pipe. This process is why the engine can consistently burn fuel at a hot enough temperature to maintain velocity. 

If no oil were in the engine while it was running, the piston friction would heat up and severely damage the seals around it.

Most of the time, using 5W-30 in place of SAE 30 will damage your lawnmower’s engine because it contains harmful additives that work in larger engines. Doing so will result in horrible consequences for your engine and pocketbook. Larger engines, after all, have the design to handle different proportions of additives.

However, in recent years, lawnmowers have been manufactured to function on multi-grade engine oils like 5W-30. It would benefit you to check the manufacturer’s guidelines about which oil to use and which ones to avoid. 

But, overall, if you are someone who lives in a mild or warm climate, then you should not have to worry that much about it. SAE 30 should be fine, even if you need to wear a jacket while mowing.  

Can You Mix SAE 30 and 5W-30

It depends on how much of a ratio you use and how long you continue to run your lawnmower with the new oil cocktail. 5W-30 is multi-grade motor oil, whereas SAE 30 is a single grade. Mixing the two will dilute the characteristics of 5W-30 and likely result in poor engine performance. 

Although it is not advised to mix SAE 30 and 5W-30, some people do and claim that their engines have and continue to perform as if everything were the same. 

With that being said, it is best to consult those who work directly with engine oils regularly or those who are formally educated in that field before pouring your new mixture into your lawnmower’s engine. While there may be some truth to people’s anecdotal claims on internet message boards, it is in your and your equipment’s best interest if you can speak with an actual human being to see if mixing the two oils would be fine.

Could Mixing Oil Damage the Mower Engine

The chances are high that you could be dealing with a dead lawnmower if you decide to mix SAE 30 and 5W-30 oils. The main reason is that a lawnmower engine is not made to handle the additives found in multi-grade oils like 5W-30. Even if the engine continues to function like before you added the mixture, it will probably result in long-term detrimental effects. 

Seeing as manufacturers have recently made developments on lawnmowers and other small-engine equipment that function on multi-grade oils like 5W-30, mixing the two, in this case, would have little to no effect on your engine. 

SAE 30 oil is cheaper than 5W-30 oil. When you mix the two in an engine that is only designed for single-grade oils, you are putting your small engine at risk and paying more to do so. 

The 5W-30 and SAE 30 are just two quality options for people who want to effectively use lawnmowers. With so many brands, it is best to trust quality certifications like the API symbol when shopping for new oil. API has certified 500 companies, meaning you can trust their knowledge of oil quality.

Verdict: SAE 30 vs. 5W-30: Which Is Best in Lawn Mowers

Unless your mower is a newer model specifically designed to handle multi-grade oils like 5W-30, the best and safest option is to stick with single-grade oils like SAE 30. Doing so will prolong the life and functionality of your lawnmower engine. Not only is it the safest option, but it is also the cheapest.

SAE 30 differs from 5W-30 in terms of operating temperature, viscosity, pressure, and composition. Since SAE 30 is designed for small engines like lawnmowers while 5W-30 is designed for complex engines like the kind found in vehicles, it is the most suitable oil for yours.