Another member posted this a thread; I think this is the official oil used:
https://www.ebay.com/itm/7-Liters-Q...qdb8lC6:sc:USPSPriority!97034!US!-1:rk:1:pf:0
https://www.ebay.com/itm/7-Liters-Q...qdb8lC6:sc:USPSPriority!97034!US!-1:rk:1:pf:0