Can I mix oil viscosity and brand?

[SupremePossum]

I made a thread recently where I accidently put some 5W-20 in my lawn mower, which calls for either 10w30 or 5w30. I still have most of a quart of the Mobil 1 5W-20 laying around with no vehicles for it (My old Ford Focus took it)

I also have a quart of 10w30, and then vast stocks of 5w30 (I keep a lot for the standby Generac)

Quite a lot of posts where people are advocating for heavier weight oil for these small engines like lawn mowers and portable generators. I also have a Champion 8750w generator filled with 5w30

First question, being in Houston where its hot, but also does freeze in winter. is 15w40 an advisable oil for my mower and portable generator? Or should I just stick with 5 or 10w30?

Second question, lets say I get some 15w40, can I mix in all my spare 5W-20 and 10w30 in with it to make an oil concoction, so it doesn't go to waste?

 

[JavierH19]

Mix it all up like a bartender.

 

[SupremePossum]

With ice, yeah?

 

[Kira]

Mowers aren't picky.
The generator is a piece of gear you might want to keep within spec given the likelihood of a cold Winter start up.
Yes you can "sneak dribble" your leftovers into your oil changes/top-offs.

 

[mrsilv04]

My biggest concern about thinner oils in a smaller engine, is that consumption could go up. I don't think it matters to the engine otherwise.

 

[Bud_One]

I live north of Houston and run 15w40 in all my OPE to simplify .
When we froze in 2021 and it got down to 9 degrees , my generator (2008 Briggs 10 hp) with 15w40 fired up in two pulls.

 

[cptbarkey]

I do it all the time in my entire residential and ranch fleet of equipment. a few months ago i threw in 0w20, 5w30, 5w40 total quartz singles into a larger jug and thats one OPE cocktail I have at the ready. I do not lose sleep over "additive clash." Nothing has exploded yet.

 

[4wd]

I live north of Houston and run 15w40 in all my OPE to simplify .
When we froze in 2021 and it got down to 9 degrees , my generator (2008 Briggs 10 hp) with 15w40 fired up in two pulls.

Just hit Blue Water Seafood there for my last dose of half shells and a platter (I stop half shell when it warms up) …

 

[#18FAN]

Mowers aren't picky.
The generator is a piece of gear you might want to keep within spec given the likelihood of a cold Winter start up.
Yes you can "sneak dribble" your leftovers into your oil changes/top-offs.

Use 15W40 he will never see 0F Temps or below.

 

[jeepman3071]

My biggest concern about thinner oils in a smaller engine, is that consumption could go up. I don't think it matters to the engine otherwise.

This.

You can run 0w20 in a small engine if you want. Mixing brands, viscosity, it doesn't matter as long as you keep the level at full.

 

[wag123]

I made a thread recently where I accidently put some 5W-20 in my lawn mower, which calls for either 10w30 or 5w30. I still have most of a quart of the Mobil 1 5W-20 laying around with no vehicles for it (My old Ford Focus took it)

I also have a quart of 10w30, and then vast stocks of 5w30 (I keep a lot for the standby Generac)

Quite a lot of posts where people are advocating for heavier weight oil for these small engines like lawn mowers and portable generators. I also have a Champion 8750w generator filled with 5w30

First question, being in Houston where its hot, but also does freeze in winter. is 15w40 an advisable oil for my mower and portable generator? Or should I just stick with 5 or 10w30?

Second question, lets say I get some 15w40, can I mix in all my spare 5W-20 and 10w30 in with it to make an oil concoction, so it doesn't go to waste?

I disagree with jeepman on this. Mixing different brands and/or types of motor oil could cause problems with incompatible additive chemistries, and using 5w-20 or 0w-anything in an air cooled engine in the Houston heat is asking for trouble.
How many ounces of oil are in your lawnmower? This strikes me as an example of "trying to squeeze a nickel to make a dime". Dump the 5w-20 and install the oil that the factory recommends, 10w30. You can also use 5w30 synthetic (or even straight SAE30 in Houston).
Avoid motor oils with a wide Xw-X spread to minimize the amount of VII improver that is added to the multigrade oils. VII in an air cooled engine is not good. Synthetic oil contains less VII than conventional oil, and SAE30 has NO VII in it.

 

[kschachn]

You can run 0w20 in a small engine if you want. Mixing brands, viscosity, it doesn't matter as long as you keep the level at full.

Running a 20-grade oil in air-cooled OPE in Houston is beyond foolish.

 

[jeepman3071]

The key to my statement is keeping it full. If you feel your engine will consume the oil faster than you can check it, then yeah, you shouldn't be using a xw20.

 

[Warstud]

You can .... Just don't get caught

 

[kschachn]

Second question, lets say I get some 15w40, can I mix in all my spare 5W-20 and 10w30 in with it to make an oil concoction, so it doesn't go to waste?

Here are a few previous threads on mixing oils. There is also the Widman caclulator to determine your resulting grade.

https://bobistheoilguy.com/forums/threads/mixing-oils.315053/
https://bobistheoilguy.com/forums/threads/mixed-oil-debate.334979/
https://bobistheoilguy.com/forums/threads/mixing-oil.159202/
https://bobistheoilguy.com/forums/threads/mixing-oils.226210/
https://bobistheoilguy.com/forums/threads/mixing-oils-for-desired-viscosity-index.196806/
https://bobistheoilguy.com/forums/threads/mixing-motor-oil-brands.13615/
https://bobistheoilguy.com/forums/threads/mixing-different-weights-of-oil.228891/
https://bobistheoilguy.com/forums/threads/mixing-oils.325422/
https://bobistheoilguy.com/forums/threads/mixing-oils.163365/
https://bobistheoilguy.com/forums/threads/mixing-oils.120334/
https://bobistheoilguy.com/forums/threads/mixing-oils.111570/
https://bobistheoilguy.com/forums/threads/mixing-oils.2042/
https://bobistheoilguy.com/forums/threads/what-exactly-is-wrong-with-mixing-brands.202306/
https://bobistheoilguy.com/forums/threads/mixing-oils.122427/
https://bobistheoilguy.com/forums/threads/mixing-viscosities.3554/
https://bobistheoilguy.com/forums/threads/mixing-oils-again.85143/
https://bobistheoilguy.com/forums/threads/more-mixing-oils.148701/
https://bobistheoilguy.com/forums/threads/can-you-mix-viscosities-of-oil.157147/
https://bobistheoilguy.com/forums/threads/mixing-viscosities-and-or-brands-ok-or-no.349001/
https://bobistheoilguy.com/forums/threads/mixing-oil-weights.106037/
https://bobistheoilguy.com/forums/threads/mixing-different-oils.240247/
https://bobistheoilguy.com/forums/threads/mixing-oil.333464/
https://bobistheoilguy.com/forums/threads/mixing-oils-of-different-weights.186388/
https://bobistheoilguy.com/forums/threads/blending-kirkland-and-supertech-oils.367418/
https://bobistheoilguy.com/forums/threads/mixing-different-weighted-oils.196640/
https://bobistheoilguy.com/forums/threads/frankenoil-thoughts-on-mixing-viscosities.331446/

 

[kschachn]

The key to my statement is keeping it full. If you feel your engine will consume the oil faster than you can check it, then yeah, you shouldn't be using a xw20.

That's one key. The other (and at least equally important key) is to prevent metal-to-metal contact in the engine as the oil thins due to heat. An inadequate MOFT will kill the engine pretty quick. An engine full of oil at a temperature where the film thickness is insufficient won't prevent failure just because of the quantity.

 

[goingplacesanddoingstuff]

You can mix brands, but it’s not ideal.

Mixing viscosities of the same brand is generally perfectly fine. I’ve gotten rid of 20 weight oils by mixing with same brand 40 and 50 weights. No issues.

 

[wpod]

I don't understand why people have the with mixing different viscosities or brands questions etc.

 

[SupremePossum]

I don't understand why people have the with mixing different viscosities or brands questions etc.

Because sometimes questions with perhaps obvious answers, do not have obvious answers

It costs nothing to post and ask

 

[kschachn]

I don't understand why people have the with mixing different viscosities or brands questions etc.

That may not be all they don't understand.