Nothing to worry about. I decided to do an emergency oil change on my Honda 1.5t oil dilution nightmare when the oil level rose about an inch above full. I refilled with portions of Mobil1 0w20, castrol edge 5w30 and Ravenol RUP 5w-40. Didn't notice any change at all and it was certainly better than running around with over a quart of gasoline in the sump
Just bought a Subaru with an EJ253. The previous owner just changed the oil and he used LM Molygen. I plan to use M1 HM. Can I top off as needed with M1? Thx.
You could add five different brands (one quart each) of SN Plus oils and there's nothing to be concerned about. It's all compatible.
Maybe next year I'll run 1-3/4 quarts of all three oils in my Signature and get it analyzed by Blackstone at my usual 4k. I'll bet they will like the results.
Oils are guaranteed to be miscible if they pass ASTM D6922 which is part of the API licensing requirement. Molygen is not API licensed so you don't automatically know it passed that test, but LM would be fools if it did not (in addition to being subject to multiple lawsuits). But contrary to what someone posted in this thread the oil is not API SN, it is only "recommended for" those applications that require API SN. It is up to LM as to whether it actually meets and achieves all of the requirements of that license.