Can I Use 5w30 Instead of 10w30 in My Lawn Mower?

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I’ve seen many people ask this question on different forums: Can I use 5W30 instead of 10W30 in my lawn mower? 

The simple answer is No.  

You can’t use any type of oil for your lawn mower because you feel that’s the best thing to do. There are several factors to consider before using a specific oil brand for your lawn mower.

In this article, you will find a list of factors to consider before picking specific oil for your mower’s engine. 

In addition, I talk about the differences between 5W30 and 10W30 oil types. This will help you make an informed decision in choosing the most appropriate oil for your lawn mower.

What is 5W30 Oil

What is 5W30 Oil?

5W30 is a multi-grade oil with viscosity ranging from 5 (lower) to 30 (higher). By default, the oil is thinner than the 10W30 engine oil in cold weather. Manufacturers designed these oils to protect the engine while warming up.

The first number, 5, represents the oil’s thickness or viscosity in low temperature. This is also known as winter rating. 

The second number, 30, stands for the oil’s thickness at higher temperature. It is the oil’s viscosity when the mower’s engine is running. The “W” before 5 stands for “Winter.”

The oil’s viscosity value of 5 in winter implies that it is thinner or less viscous at low temperature. The reverse is the case at high temperature when it is thicker, as its 30 rating indicates.

Consider using the 5W30 oil if you live in an area where seasonal temperature variations are common. The oil will perform well in a temperature range between -30oC and 35oC. 

If you use the oil at low temperatures, it flows with ease and protects the engine’s internal components.

Also Read: Can You Use 2 Cycle Oil In A Lawn Mower?

What is 10W30 Oil?

The 10W30 oil has a viscosity of 10W at cold temperature and 30 at high temperature. Thus, at low temperature, the 10W30 oil is thicker than the 5W30 oil. Why does this matter?

The higher viscosity provides better lubrication for the engine’s critical parts. The thicker 10W30 oil reduces engine performance by increasing its resistance. The resistance increases fuel consumption and thus lowers fuel efficiency. 

Also Read: SAE 30 vs 10W30: Which Is Better?

What’s the Effect of Oil Viscosity on a Mower Engine?

Oil’s viscosity grade has a profound effect on a lawn mower’s efficiency. High and low viscous oils perform well under different conditions.

Thanks to their low thickness, thinner oils thin out with ease. The thinning may damage the engine and some of its components. It may increase the friction between the engine’s internal parts.  A thicker oil would have lubricated those parts and prevented the friction.  

High viscous oils lubricate the engine’s internal parts and prevent friction. Too high viscosity can result in increased engine drag and high oil temperature.

Thinner engine oils flow quickly and easily around the engine. They thereby lubricate a cold engine without much ado when you start it. The lubrication helps the engine come to life immediately when you power it on.    

Too thin oil can splash from the internal components of a working mower. The splashing will reduce the quantity of oil in the engine. The reduced oil may hurt the engine as it tends to wear out quickly.  

Thicker oil prevents the oil from becoming too thin when the engine is operational and hot. It only lubricates and separates the engine’s different components.

What Factors Determine the Right Oil for Your Lawn Mower?

Knowing the oil that suits your lawn mower perfectly will increase its performance and extend its lifespan. When deciding whether to use 5W30 oil instead of the 10W30 oil, consider these factors:

Temperature

One of the major factors that determine the right oil for your lawn mower is the prevalent temperature. 

The 5W30E oil is the best for your lawn mower if you intend to leave the oil in the engine during the winter. If you won’t drain the engine in summer, use the 10W30 oil.

More so, consider the 5W30 option if you live in Canada or some parts of the United States where temperatures can drop below zero. Since this oil can operate at low temperature (-30 degree), it is ideal for such cold places.

It is also the oil of choice for residents of warm climates where temperature up to 35 degrees Celsius is common. Thus, 5w30 oil is a more versatile oil brand that can work well in a wide range of temperatures in cold and warm climates.

Manufacturer’s recommendation

Manufacturer’s recommendation supersedes any other factor. Engine manufacturers understand each engine’s needs. They recommend the best oil viscosity for specific engines. You can ignore their professional recommendations when choosing the right oil for your mower’s engine at your peril.

Machinery Lubrication offers a helpful tip to help you make the best choice. 

To choose the right lubricant for your vehicles, use the viscosity grade(s) recommended by the original equipment manufacturer (OEM) for the life of the engine and especially during the engine’s warranty period. Viscosity grades are primarily recommended according to the expected ambient temperatures, particularly the starting temperatures.

Also Read: Best Oil for Kawasaki Lawn Mower Engine

What Happens if You Use the Wrong Oil?

You may wonder what the likely outcome is if you replace the recommended 10W30 oil with the 5W30 oil. Upkeep, a firm that assists maintenance teams, highlights the danger of making such a costly mistake. 

It says: 

Inappropriate oil viscosity can result in occasional contact between machine components. When this goes unchecked, you’ll start experiencing damage and problems with equipment.

Don’t use any type of oil for your lawn mower without considering their suitability for its engine. Consider your operational temperature as well. The 5W30 oil is recommended for extremely cold temperatures. 

Using the 10W30 oil under such a condition exposes your engine to tons of problems. The potential implication of the wrong oil on your engine deserves your consideration as well.

So, if your lawn mower manufacturer recommends the 10W30 oil brand for your engine, total compliance with that instruction will prolong the mower engine’s life expectancy.