Looking at two fairly serious VOAs on Oil-Club.ru. Google Translate only goes so far, but it reveals enough to pique one's interest. Mobil 1 ESP Formula 5W-30 Red Line Euro Series 5w-30 Both also apparently have esters, and this is one aspect on which I wanted to compare them. At least one person on that forum seems to be very confident that the M1 is around 5% ester, referring to a number (35) that I think I see on the VOA. Can anyone tell whether this seems reasonable? The same number on the Red Line VOA is much higher (95) but I don't know what it means. Does it suggest the Red Line has higher ester content? If so, by how much (roughly)? And how might that mesh with the fact that the Mobil 1 has a much higher TAN (usually higher with ester content)? One forum user suggests that the esters in the Red Line are apparently very neutral; what does that mean for how they might behave in the formulation?