While your lawn mower might have a smaller gas engine, there are still a ton of moving parts that require oil. But not all motor oil is the same. Since there is a huge variety of motor oils out there, it can be tricky to figure out which kind you need. When it comes to lawn mowers, two of the most common oils used are SAE 30 and 10w30. These two oils each offer their own benefits because they have slightly different characteristics. This is true for most motor oils.
Motor oils are usually classified by how they act at different temperatures, and their viscosity. At warmer temperatures, oil is thinner (less viscous) and flows more quickly, while the opposite is true at lower temperatures. Because of this, some oils have additives that change their thickness or viscosity so that they can flow correctly even when the engine is really cold or really hot.
SAE 30 vs 10w30 (The Short Version)
The winner of best oil between SAE 30 vs 10w30 needs to be chosen with operating conditions in mind. Basically, SAE 30 works great in older mowers, but most newer mowers call for 10w30. SAE 30 is also better in warm conditions while 10w30 can accommodate colder ones as well. Aside from these factors, be sure to consider what the manufacturer recommends for your lawn mower.
Is SAE 30 the Same as 10w30?
Although both motor oils are commonly used in mowers, SAE 30 and 10w30 are not the same. To explain this in more detail, let’s talk a little bit about how motor oils are classified.
First, take a look at the “30” that you see in both oils. This number represents the measurement of viscosity that has been made a standard by the Society of Automotive Engineers (SAE) at 100 degrees Celsius. Both SAE 30 and 10w30 have a viscosity grade of 30 while hot.
Next, let’s talk about the “10w” that you can see. This is another viscosity grade but is rated for cold temperatures (represented by “w” for winter). What this tells us is that 10w30 has been rated for different viscosities at hot and cold temperatures.
So, using this information, we can determine that SAE 30 is what’s known as a single-grade oil. Again, this is because its viscosity is only rated one time while hot.
10w30 oil, on the other hand, is known as a multi-grade oil. At cold (winter) temperatures, it will have a viscosity grade of 10, and when hot, it will have a viscosity grade of 30. This is accomplished through the use of oil additives to change the properties of the oil. Still wondering about the differences between SAE 30 vs 10w30? I’ll cover some of their main characteristics below.
The Characteristics of SAE 30 and Its Benefits
As I started talking about in the last section, SAE 30’s main characteristic is its viscosity grade of 30 at hot temperatures. The SAE grading system runs from 0-60 putting SAE 30 smack dab in the middle. What that means is that SAE 30 has a pretty average viscosity or resistance to flowing. This oil is fairly standard and is almost exclusively used in small engine tools.
With simpler and more predictable motors, single-grade oil works great. This is especially true for older model lawn mowers. Another perk of SAE 30 is that it is typically less expensive than multi-grade oils. Of course, the price still largely depends on whether you buy synthetic or conventional oil (but I’ll save the debate between synthetic and conventional oil for another day).
The Characteristics of 10w30 and Its Benefits
Again, since 10w30 has two different viscosity ratings based on temperature, it is a multi-grade oil. While hot it is rated at 30 viscosity, and when cold it is rated at 10 viscosity. This characteristic lets the oil adapt to whatever situation the engine is in. Because of this, most larger engines, like those on passenger vehicles, use multi-grade oils.
A big reason for this is that engines need lubricating even when it is really cold outside or the engine is just starting. If you live somewhere that gets cold during the mowing season, it might not be a bad idea to use a multi-grade oil like this that has some flexibility.
Can I Use SAE 30 Instead of 10w30? (+ When It Makes Sense)
The short answer to this question is sometimes. Using a single-grade oil in place of a multi-grade oil can cause problems. In this case, however, with lawn mower engines and with oils of the same viscosity grade when hot, you might be able to get away with it.
Let me describe a couple of specific scenarios where it is okay to use SAE 30 instead of 10w30. First, if you live somewhere that doesn’t get much cold weather during the mowing season, it shouldn’t be a problem. This is because both oils will flow the same when hot. If there’s no need to worry about cold starts, you should be fine. The other time where you’re okay to use SAE 30 instead of 10w30 is if your manual or manufacturer recommends it. This would be most likely on older lawn mowers, but it’s worth double-checking.
Can I Use 10w30 Instead of SAE 30 in My Lawn Mower?
You can use 10w30 instead of SAE 30 in your lawn mower if you want. Since 10w30 has the same viscosity grade at operating temperature, you won’t run into any problems by using it instead of SAE 30.
Sometimes it is actually a good idea to make this switch. This would be the case for anybody mowing in colder climates. Since 10w30 is a multi-grade oil, the only consequence of using it is more flexibility with different temperatures. Many newer lawn mowers actually recommend the use of 10w30 in their engines. Although SAE 30 has been a traditional choice for small engines, the viscosity range of 10w30 oils is being used more and more often.
Still wondering, is SAE 30 the same as 10w30? All in all, they are very similar but they are not the same. Manufacturer guidelines are always the best bet to follow, and if that doesn’t clear things up enough, think about your climate. Though it might not seem relevant, it’s a good way to figure out which oil is best for your mower. Got an old mower and live somewhere that is always hot? SAE 30. Newer mow in a place where the temperatures dip down during mowing season? Go for 10w30.