Does Mobil 1™ or AMSOIL provide the best protection for longer drain intervals?
“I read on the Internet that AMSOIL has interval change of 25,000 miles and say they back it up with oil testing done on fleet commercial trucks. What is your opinion how Mobil 1 vs. AMSOIL compares? Can you quote if testing has been done and which is better? I would really like to know who makes the best oil and why Mobil™ says to change oil at recommended intervals by the manufacturer. If Mobil 1™ Extended Protection is used, the change interval is still only 15,000 miles compared to AMSOIL saying 25,000 miles. I currently use Mobil 1 in both my Toyota Tundra and 4 Runner, but AMSOIL claims of 25,000 miles with fleet testing gets me thinking maybe I should change to AMSOIL. Your honest reply citing professional standards used would be appreciated by many of the public (i.e., ASTM). I really would like to know who has the best protection and why. Your reply is greatly appreciated.”
Greg Galbreath, Palmdale, California