answer:Personally, I think your boyfriend is screwed. I once took my car to a Valvoline store in the city, about 2 hours away. The oil light started coming on, almost before I got home. I drove it that way for a while, knowing the oil had just been changed, and it had to be a fault. Nope! There was no oil in the car by the time I checked it. There is a oil and lube place locally that doesn’t re-fill the car completely. I went there twice. The first time the oil light started coming on at 2,000 miles! I took it back and mentioned it. That time the oil light started coming on at about 1,500 miles! Short of convincing the AG to do an investigation, I don’t know how anyone would ever prove it. The re-filled oil would have to be drained and measured on the spot for it to be valid. He has no proof that the oil was shorted and he has no proof that low oil caused the knocking. I don’t mean to be harsh…I just don’t think there’s reason to give you any hope, here.