Had to substitute one litre because for some reason Rotella gas truck no where to be found in stores, and I wasn't buying 2, not for cost but I just don't believe in having oil stashes, taking up space as I live in a condo, it's one level and I have a shed but hate leaving oil exposed to elements for 6 plus months in winter. And yes I like archoil, it works...every vehicle I have put it in, Ive taken before and during dumping archoil in sump, within a minute it dropped noise at minimum 2 db. As well as before and after cold start videos and sound checks in minus 30 degree weather. So therefore I believe it does what's it's aimed to do, help with friction. I know you anti snake oil bandits are going to start chirping and bashing, and I do not even care, because you have people out there who once Castrol slaps "magnatec" on a bottle all of a sudden start drooling over it. Anyway here is what's going in, and as much as I hate paying for UOA because this vehicle was not new to me, I think I will get one done, top end is spotless but still would like to see how this concoction works.