No but Valvolines Synthetic 15 ounce bottle at a treat rate of 1 ounce per quart lowers Fe and lead time after time through analysis from what I've seen . It's cost efficient with 3 treats per bottle .
There's a couple additives out there promoted to reduce oxidation . Even with the best synthetics . I personally cannot see why someone using a good "real" synthetic with exeptionaly low NOACK would place a additive like these in there oil, with their probable very low NOACK . Whats the NOACK of solvents ? See what I mean ?
If I were having trouble with oxidative thickening I'd switch oils but I don't , so I wont't
Anyway , when was the last time you saw a GFIII mineral based oil thicken out of grade ?