I check it every oil change and there's always a couple ounces of oil in it Frankly i haven't seen any controlled scientific evidence of oil can can efficacy other than many videos with people holding cans full of oily sludge that i presume was trapped in an oil catch. Sometimes it's milky from condensation
Oil Catch Can for Subaru – Lawn & Tractor Co.
It's a small amount but.
Better engine longevity, reduced intake deposits
My buddy had one on his brand new vehicle, it froze up in winter causing oil to burp out the rear main seal He immediately removed it and he dodged a bullet so far, as it has remained dry.
