5w30 vs 10w30 Honda Lawn Mower Oil
By: Leon Rhodes
Honda recommends using SAE 30 oil in their lawnmowers, however, you can use 5w30 and 10w30 multi-viscosity oil in your Honda lawn mower without any problems. The difference between 5w30, 10w30 and SAE 30 oil is how well they flow when cold. When hot, all three oils provide the same 30 viscosity rating, they are the same.
5W30 oil is OK for use in lawn mowers that recommend using SAE 30 oil. This is because 5w30 and SAE 30 oil provide the same protection once the engine is hot, meaning they flow at the same rate and offer the same amount of small engine friction protection.
10W30 oil can be used in your Honda lawn mower, it provides the same protection from the damaging effects of heat that you expect from an SAE 30 oil. As long as the number after the w in your oil type is 30 the oil will provide the same amount of protection as an SAE 30 oil.
Which Lawn Mower Oil To Use
The best oil for you Honda lawn mower is always going to be the one recommended in your Honda manual, which is almost always SAE 30 or Honda brand mower oil. If you don't have a Honda mower manual, or you don't have the recommended oil, you can use 10w30 as a safe substitute for SAE 30 oil.
You don't have to use Honda oil in a Honda lawn mower, in fact you can probably save money with a cheaper but just as effective alternative. The reason Honda offers their own brand of oil for their mowers, besides profit, is to control oil quality. Advancements in oil technology took care of that problem.
SAE 30 is not the same as 10W30. SAE 30 is a single viscosity oil meaning it flows more slowly in a cold engine. 5w30 and 10w30 oil are multi-viscosity oils, they flow better in a cold engine and provide the same protection as SAE 30 oil when hot.
Lawn Mower Oil Thickness
SAE 30 is thicker than 10W30 until it warms up. This means a cold start with SAE 30 is slightly harder than a cold start with 10w30 and the engine is less protected during the warm-up period. Engine oil that flows more freely can coat and protect engine components better when they are still cold, thus reducing wear and tear on your mower engine.
Honda recommends synthetic oil in their lawn mower engines but not until a new engine has had at least 5 hours of use. Enough wear to properly seat the valves is required before switching from regular oil to synthetic oil.
The Difference Between Oils
The difference between SAE 30 oil and 5w30 oil is that 5w30 oil will flow better and better protect your Honda mower engine when cold. As the engine warms up the 5w30 oil will thicken to provide more protection. Once hot both oils will provide a 30 viscosity protection rating.
You can use 5w30 instead of SAE 30 oil in Honda mower engines but not 5w20(or less). The number after the w is the important number and since Honda recommends SAE 30 you want to make sure not to use anything less than 30. Engine damage can happen if you do.
If you put car oil in a lawn mower nothing bad will happen as long as you make sure the viscosity rating is high enough, which means at least 30. SAE 30 or any oil rated 'w30' should be OK.
Source: I have Over 35 years of experience with small engines, LR. You can find a copy of your Honda lawn mower manual to download here.