It's not a red-hot emergency, but I am looking for a winter oil that does not contain esters. I have a computer issue with PDFs and cannot open CAS# info and am basicly not an expert in them anyway. Can someone look for me? The reason being that my ARX treatments are running late into the season and I can't get away from ester-less oils until the seals are cleaned. Other choices include Rotella Synth 5w-40 and if I cheap out, Motorcraft 5w-30.