Mixing Oils

[macrafic]

Wondering if it is OK to mix oil brands and viscosity. Here is the situation.

I live in Minnesota. During the warmer months, I use a straight weight oil (Aeroshell W100 Plus). During the colder months, I use a multi-weight (Phillips 66 X/C 20W-50). I generally only fly 50-60 hours per year, however. So, come oil change time, I only have 25-30 hours on the oil and filter. My target is to change both at least every 50 hours. (My oil filter is a severe PIA to change!!!!!!). So, am contemplating changing the oil at 25 and only changing the filter every other time (50 hrs). And, of course, cutting the filter open and analyzing any metal, or send the filter into AvLabs and let them analyze it.

The issue is the quart of oil that remains in the filter at oil change time. This oil would mix with the 6 quarts of different brand and viscosity of oil that is added after draining the oil.

My main questions: Is there a problem with this?

BTW, if you want to comment on changing oils on a seasonal basis, I am open to thoughts. My plane is hangared, and I do NOT start the plane in the colder months without having it plugged in (heated). I can't, however, guarantee that I would have this heating capability if traveling to other cold places during the winter so, avoid any possibility of cold starts, I change the oil to (mult-viscosity) to make it as easy on the engine as possible. I also worry about running multi-viscosity in warmer places I may travel to during the summer months (Arizona, Texas, etc.). So, I change the oil to a single (and heavier) weight. Truth be told, we may travel to such places 2-3 times per year, if even that. Still, one cold start and the damage that is done to the engine... Thoughts?

[BobTurner]

Generally speaking, oils - unlike greases - are compatible with one another. So no need to worry about the quart in the filter.

[Bicyclops]

Or just run the XC 20-50 year round. It works as well as the straight weight oil in the summer.

Ed Holyoke

[odens_14]

Originally Posted by Bicyclops

Or just run the XC 20-50 year round. It works as well as the straight weight oil in the summer.

Ed Holyoke

+1, that's what I do and live in MN as well.

[Bicyclops]

Originally Posted by odens_14

+1, that's what I do and live in MN as well.

Yah, I'm in SoCal and I've been running XC for years. If it works for you guys in the real cold, it's been fine in the pretty darned hot. They've got the new version (Victory) with the anti-scuff additives in it for all the flat tappet folks.

Ed Holyoke

[Tankerpilot75]

Originally Posted by BobTurner

Generally speaking, oils - unlike greases - are compatible with one another. So no need to worry about the quart in the filter.

That?s what I?ve heard too.

[abwaldal@gmail.com]

I'm gonna second the multi-vis oil. I use AeroShell 15w50. My 0-360 oil useage went down when I switched from W100 and didn't look back years ago. This is the age of multi-vis oils so why not take advantage of it. My 2019 honda accord uses 0-20 synthetic and uses no oil in 10,000 miles. Crazy to burn so much oil in our Lycosourus engines. But I know why being air cooled big cyl gaps and all.
Make your life easier not more complicated.
Art

[Kyle Boatright]

Originally Posted by BobTurner

Generally speaking, oils - unlike greases - are compatible with one another. So no need to worry about the quart in the filter.

The mil-spec's for aviation oils require them to be compatible.

[Bavafa]

3rd for multi weight year around. Also please keep in mind that the Lycoming states 50 hour run time or 4 months for oil change.

[jbDC9]

Originally Posted by abwaldal@gmail.com

I use AeroShell 15w50. My 0-360 oil useage went down when I switched from W100 and didn't look back years ago.

Interesting... a few years ago I switched from Phillips XC 20W-50 to Aeroshell 15W-50 and my consumption went up! I?d have switched back to the Phil XC but I had 8-10 cases of the Aeroshell to run through; I had a free stash of donated oil, might as well use it...