Have a few oils to choose from, except the recommended 10w-30..

Aug 10, 2015
Hey folks..

I just bought a toro Recycle Lawn Mower with the honda GCV 160 engine this spring and need to change the shop oil, but I don't have any or SAE 10W-30 detergent oil. I do have some old SAE 30 though..

I also have..
Mobil one 5w-30
Valvoline HD Diesel 15w-40
Rotella T 15w-40 allot
Rotella T6 5w-40

Granted, the wheels will probably fly off before the engine has any problems, but I figured I'd ask you kind and knowledgeable people people anyway.

Should I go out and buy some SAE 10W-30? Or will one of the other oils I have perform as well as the recommended SAE 30 or SAE 10W-30?

Last edited:
You probably would never know a difference with any of those you listed (and, likely, neither would the mower), but why not buy a $6 quart of synthetic 10w30 that'll last two oil changes/two plus years, and give you the peace of mind that you'd stayed within the spec?

If I remember correctly from our GCV190's manual, the chart is kinda strange and shows both 5w30 and 10w30 on the same bar ( like [5w30 * 10w30] but the 5w30 first, implying its use at a lower temperature, though they aren't separate bars as they should be if that was the implication). If you wanted to use the 5w30, I believe that it is on the chart in some capacity, and being in Iowa you might run the mower at cooler temps in the fall and spring to chop leaves and such, where 15w40 might be a touch thick. In ours, I've always just used 10w30 synthetic in some form (M1 or QSUD or Rotella, usually), because it has such a small sump and that way I don't have to overthink it.
There is no "e" in Mobil. Mobile is a city in Alabama.

Joking aside, any of the latter three would be my personal choice, but all will work just fine.
SAE 30 will be perfectly fine, assuming you don't try cutting your grass during the winter, either flavor of 15W40 would be fine too, I'd go with the 5W40 if for some reason you're using the mower in freezing temps.
Of those I would pick the SAE 30, followed by the HD oils.

In fact, I just changed oil in my Honda mower today; conventional SAE 30 out/in. It runs just like it did with the various 10w30, 10w40, 15w40, 5w30, and 20w50 I used over the past 24 years in that mower! :) Even though I didn't always do this, I think it is best to pick a small engine oil or HD oil instead of a car oil...
It's a new engine, right?
Use up the SAE 30 during break-in. You should change the oil a few times during the first running hours anyway to flush out the initial wear metals. Might as well put that stuff to use. Then, use any of the other oils.

I use 10W-30 in my GCV160 and generators, although I recently bought some 5W-40 on sale that will go in this fall.
I have torn into these engines many times and am very impressed with the quality. Id use a thinner oil so the upper crankshaft journal gets splashed to the max.

Only on engines that are ran with dirty oil, or low on oil, I have seen the upper bearing show signs of galling before any other journal shows wear.

Shell Rotella makes makes an awsome 5w-40 diesel order.
The Honda engines do not run hot when compared to some other brands. Oil temps will be about 190-210. The 5W-30 will work just fine and M1, 5W-30 is in fact what I use in my Honda 190 powered mower. However, the T6 is a more robust oil and would be a better choice if you plan on torturing the thing.
I would be a big spender and purchase a quart of 10w30 Mobil or Pennzoil and know I am using the recommended viscosity. Ed
Definitely some logic to this answer only I would suggest a gallon of T5, it will last 7 years if doing annual changes. Wally has it for around $18 which works out to about $2.50 a year.