Usually written by reps from oil suppliers that don't have "old car oil". Northland Petroleum here in town supplies all the lubricants for John Deere tractors built here. I asked about "old car oil" and they said they may have a few old barrels in the warehouse. It has "seal swell" in it to soften seals in old engines. I didn't get into ZDDP levels. I should get ahold of Scot again and make a deal. Bottling and shipping it would be a pain though.