When it comes to changing or topping up the oil for your lawn mower, you need to make sure you’re using the right type. If you’re not careful, you could cause irreparable damage to the engine.

To ensure you use the correct oil, you need to understand the oil grading system.
Right now, this may seem very confusing to you, but with a little research, it can be quite simple to find out what oil your mower requires.
The ratings of oil go from 0 to 60 with the lowest numbers representing the least viscous (thinnest) type of oil, whilst the most viscous (thickets) oil type is represented by the higher numbers.
Oil is graded by how easily it flows, which, in turn, is determined by its viscosity and weight. But, sometimes, two different oils can have very similar, or even the same ratings.
Therefore, how do you choose which one to use?
Today, we are going to discuss two oils that have very similar ratings – SAE 30 and 5w30. Although similar, once we delve into these oils, we will find that there are a number of differences.
Let’s get started.
SAE 30 VS 5w30: Are They The Same?
Introduced in 1905 by Henry Ford and Andrew Ricker, the Society of Automotive Engineers (SAE) aimed to design a specific classification system to identify the thickness of oils, also known as their viscosity.
Therefore, people could then understand what type of oil they needed for all engine types.
When you can determine an oil’s viscosity, you can find out how long it will take for the oil to flow to the engine at 0 degrees Fahrenheit.
If the consistency of the oil is higher, it will take longer to move through the engine.
As you can see, both SAE 30 and 5w30 oils have the same viscosity rating of 30, but this is when the oil is hot. When cold, the differences start to become clear.
SAE 30 is a single-grade oil. This basically means that it is rated for just one time at an extremely high temperature. The high-temperature rating is represented by the number “30”.
5w30 is typically used in the automobile industry. Unlike SAE 30, 5w30 is a multi-grade oil, meaning it can withstand very low temperatures.
This is why it is used in cars but not as commonly used in lawnmowers.
The high-temperature rating of 5w30 is the same as SAE 30 at 30. However, because it is multi-grade oil, it has two ratings. For cold temperatures, it has a rating of 5.
The low-temperature grade is represented by the letter “W”, which symbolises winter.
These are the fundamental technical differences between both oil types.
Let’s explore the uses of these oils and the characteristics of both, so you can better understand which one you will require.
SAE 30 Characteristics
SAE 30 is frequently used for small engines. Being a single-grade oil, it tends to be pretty affordable and simple.
SAE 30 oil has been considered a reliable grade for lawn mower use over many years. This is because it works extremely well under the temperatures most lawnmowers use.
Unlike motor vehicles, cold starts are not a common concern with mowers, as they are typically used during the hotter months of the year. Therefore, SAE 30 is deemed a safe and trusted grade of oil for mowing.
But, if you need to operate an engine under freezing conditions, multi-grade oils are the better option.
5w30 Characteristics
5w30 oil has a very low winter rating. This means it can withstand incredibly cold temperatures.
For motor vehicles, this multi-grade oil is a godsend. This doesn’t just include cars; planes, trains, and motorbikes benefit from using this cold-resistant oil, too.
5w30 maintains a good viscosity at freezing cold temperatures. So, if you need to start an engine in a very cold climate, this oil will help.
As we mentioned, mowing is generally left to when the weather is warmer. Therefore, 5w30 oil is not used very often in mowers.
But, with that being said, it can still be used in some lawnmowers and shouldn’t have a negative effect on its power.
Is It Safe To Use 5w30 In A Lawnmower?

It can be confusing trying to choose oil for your mower because of all the different numbers.
But, when it comes to 5w30, this type of oil is safe to use in your lawnmower but we do not recommend it unless you plan to use your mower in very low temperatures.
If you want to use a multi-grade oil in your mower, you can consider using 10w30, too. Nevertheless, 5w30 is designed for use in cold conditions and is rarely used in mowers.
Is It Safe To Use SAE 30 In A lawnmower?
In general, it is completely safe to use SAE 30 oil in a lawnmower. However, you need to consider a few factors beforehand.
Firstly, you need to consider the age of your mower. If your lawnmower is new, it may have been designed to only be used with multi-grade oil.
If so, the manufacturer would have recommended using 5w30 oil, rather than SAE 30. You can contact the manufacturer to make sure.
Always check the manufacturer’s guidelines. Yes, you may think you have better things to do, but this is important to research.
If you don’t check these guidelines, you may use the wrong type of oil and damage the mower’s engine.
Another factor to consider is where you live. If the temperatures rarely get very low, such as near freezing, SAE 30 is usually the best option as 5W30 will not be required.
Is It Safe To Mix SAE 30 And 5w30 Together?
Remember, SAE 30 is a single-grade oil, whereas 5w30 is a multi-grade. If you mix the two oils together, you will compromise the characteristics of 5w30.
This can lead to poorer engine performance.
Combining the two oils is not recommended but it can be done. Some lawnmower users claim that their mower’s engines perform the same with two oils as they do with just one.
It all depends on the ratio you use. Too much of one may hinder the engine’s performance in time.
Before you decide to make an oil cocktail and pour your new concoction into your mower’s engine, we highly recommend consulting with someone who works with engine oils.
If you’re not careful, you could end up damaging your mower’s engine, which can be very costly and, of course, frustrating.
Many mower engines are not designed to withstand the additives within multi-grade oils. Although the engine may work well at first, mixing two oils could result in long-term damage.
If your mower works with multi-grade oils, though, mixing both oils shouldn’t have much of an effect, if any, on the engine.
In Summary
So, what’s the verdict? Should you use SAE 30 or 5w30 oil in your lawnmower?
If your mower is modern and designed to accommodate multi-grade oil, 5w30 can be used.
If not, though, your best option is to stick with SAE 30 oil. By sticking with the correct oil, you can ensure your mower lives a longer life and that its engine functions properly.
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