OVERKILL
$100 Site Donor 2021
Yep, that's why I suggested Polaris/OAI.With a flashpoint of 430 (I've seen a VOA of M1 0W40 that shows virgin FP of 435), we have no way of knowing for sure how much viscosity loss is due to fuel vs. mechanical shear. This is one case where it would make a lot of sense to do the next UOA with a lab that uses gas chromatography.