Since most of the popular "over the counter" synthetics are theretically formulated with GroupIII (highly refined petrolium) base stocks, does this mean that these oils contain waxes? Or are they wax free like the "true" GroupIV and V synthetics?
Group III basestocks contain waxes, and do require the use of pour point depressant (PPD) chemicals to flow at low temps:
4 Cst PAO basestock - PP of approx -75F
4 Cst Group III basestock - PP of approx -20F
How effective these PPD's remain over the course of a long drain interval is anyones guess? I do think this is a reason why PAO/Esters are preferred for most extended drain oils ...