I have always been amazed at people changing the oil at 3k or 5k. Had a 1995 Toyota Camry v6 ran Mobil 1 synthetic 10K oil changes at 200k my front valve cover started to leak when I took the cover off the inside looked brand new. Car never burned a drop of oil. Now I run Mobil 1 in my 2015 F150 and using Mobil ! EP 20K have 80,000 so far and no problems. Do you know how often 20 million dollar jet engines get the oil changed?