Can I mix oil types?

[Challenged]

We used Aeroshell 100 for my last oil change, can I utilize Aeroshell 100 Plus without issue if I need to top it off?

What about more extreme mixing of oils like brands or weights?

 

[GeorgeC]

https://www.pilotsofamerica.com/community/threads/mixing-aeroshell-15w50-into-phillips-20w50.125152/

 

[Challenged]

Thanks

 

[dmspilot]

Plus just has some extra anti-corrosion and anti-wear additives. Other than that the are the same oil.

 

[chemgeek]

Chemically, any approved aviation oil should be mixable with another. If you mix weights, you will change the viscosity slightly, but one quart out of, say 5-7 quarts isn't going to be a significant change. I managed to get rid of several extra bottles of straight mineral oil I used for break-in (and would not normally use routinely for an oil change) that way.