Popular oils that I remember:
- GC 0W-30 and the leprechauns and all the shenanigans and lore surrounding it was big when I joined.
- Motorcraft 5W-20 had a following for a while, as
@buster notes
- The RLI oils with Terry Dyson and AudiJunkie had some time in the sun
- Redline white bottle 5W-30, the "heavy" 5W-30 was popular for quite a bit, I had a decent stash of it
- TGMO 0W-20 and the "Caterham Blend" (mix), was a thing for a bit, mixing the insanely high VI TGMO product with Mobil 1 0W-40
- Mobil 1 0W-40 has had several periods of extreme popularity owing to its universality and is still recommended quite frequently
- Pennzoil Ultra 5W-30 with its super low Noack when it went GTL was a thing for a while, but then SOPUS changed the formula
- There was a brief period where Pennzoil conventional was claimed to do all manner of things it didn't, and was also claimed to be secretly loaded with surplus GTL that made it super extra awesome! It was quite popular during this period.
- Valvoline Premium Blue Restore 10W-30 discovered as a cleaning oil, was almost unobtanium, but folks were trying very hard to find it. Generated quite a stir.
- HPL's entire product line when Dave joined the forum and started directly interacting with board members, including blending bespoke offerings for members (like me), popularly from this still persists.
- And of course the current darling of the hour, Valvoline Restore and Protect in various grades