Originally Posted By: 2015_PSD
Meh...I switched from 5W-20 (Pennzoil Ultra and MS5K) to M1 AFE 0W-20 at 100K on my 2010 FX4 with a 5.4L and ran 15K OCIs for the next 60K. There was no more noise with M1 than there was with the other oils and as Modular engines go, mine was very quiet. Unless someone is using sophisticated audio equipment that is capable of measuring the difference in sound as well as comparing it and controlling the environment in which the engine is operated and the sound measured, IMHO, I write most of this off as placebo effect and Internet amplification. Granted there could be some engines that have a particular tendency towards one oil or the other, but to hear about all of these engines that make vastly more noise just seems "off".
It is off. Some are M1 haters because of the success of XM, but if you want the lubricated parts of your engine to last almost indefinitely with long OCIs, M1 oils will do that for you. I have found that out for the last 38 years.