After ending the test, I poured virgin oil into each cup and they sat until this morning. I stirred the mixtures, then drained the oils. The two M1 oils have a lot of insolubles left behind, while QS Ultimate Durability 10W-30 has almost none. The pictures are not as revealing as my eyes are. M1 0W-40 FS has roughly twice as much insolubles volume as M1 5W-40 FS does. The difference in amount of insolubles between the two M1 oils and QS UD is huge. I did not include a picture of D1 5W-40 ESP because it was not tested as long as the others, but the amount of insolubles is similar to what QS UD’s cup has.
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