Mixing oil?

[Tim Frank]

Thought I would ask here first.
I have several plastic, partial bottles of oil, some SAE 10W40, 10W30, and SAE 30.
All unused but all open.
There is enough to combine into one full quart.
It would be used in an old beater lawnmower at a lake house ... oversized wheels fitted and used to keep the hay to less than 8" , Tecumseh 4 HP engine.

I change the oil after the spring/summer season so it is ready to go in the spring.

Is there any reason that these oils will not mix? Good brands, clean and unused.
Any harm anyone can suggest.

 

[Sprig]

I doubt any harm will be done to an old lawn mower engine by mixing the oils. But why would you want to do that? If it were me I’d just buy a quart of the appropriate oil. A quart of the manufacturers designated oil certainly doesn’t cost very much. Why take a chance?

 

[Tim Frank]

I doubt any harm will be done to an old lawn mower engine by mixing the oils. But why would you want to do that? If it were me I’d just buy a quart of the appropriate oil. A quart of the manufacturers designated oil certainly doesn’t cost very much. Why take a chance?

Can't disagree; but I have them on hand, they aren't much different IMO, and I hate to just get rid of them.
That said, for $4-5- I may just do the obvious. Buy a new jug of 10W30
and mix these left overs together in one container and just use it in oiling cans.

 

[jimmbo]

They will mix fine, and the chances of damaging the Engine are Nil as you will just end up with an Oil that is tiny bit more Viscous than 10w-30