rear engine oil breather

[Learjetter]

A little oil, or a lot? Did you notice a much greater oil consumption versus normal?

Are you certain it’s not the prop grease or oil leaking?

Do you have an air/oil separator installed?

Last compression check ok? Power-stroke combustion gasses might slip past sticky rings and slightly, temporarily, pressurize crankcase and push oil/foam out the breather.

If you think it might be stuck or sludged rings, download the piston-ring flush technique free from the savvy aviation website.
https://resources.savvyaviation.com/...vent-flush.pdf

Keep us posted, please!