Engine oil Mobil or VALVOLINE

I vaguely remember a video or a study done on mobile? Syntec or something, a somewhat scientific study pulling samples every 1k miles and sending out to a lab. Bottom line was that the oil actually got better over miles and they abandoned the project at 15k miles.

I used OEM Mazda Moly 0w20 oil for most of the last 8 years, until I started getting coolant showing up in my Blackstone used oil lab reports. Switched to Mobil1 5w30 high mileage this last time, 2,500 miles ago.

I switched to Valvoline last oil changed and really like it. Feels more lively than when I changed it in the past (typically use dealer recommended Castro).

I used Mobil 1 with my Mustang. I like it for my timing chain and valve line. It’s very good. Car runs quiet.

Good old fashioned Mobil 1 for me. It wasn’t available during the pandemic so I used Valvoline Synthetic for a couple of years.

On my Giulia I've used 3 different 0W30s, and presently using Mobil 1 ESP 0W30.

I use valvoline extended protection

I've put over half a million on four different vehicles, several hundred thousand on a few others, all running Mobil One.

If I could only have one oil for all my vehicles it would be Mobil1 0w-40 because it meets all the stringent European requirements and has been shown to have a cleaning effect on dirty engines.

I have ran mobil 1 0w-40 for a long time without issue but am thinking of switching to thicker this change as it's starting to leak out one of the oil seals into compressor housing.