美國那邊有人推測的原因: Is there a shelf life on lubricants? Motul is certified to ISO 9001. According to our quality procedure, Motul products are guaranteed for two years after their production date. To ensure the validity of this guarantee, a reference sample of each production batch is kept systematically and checked on a scheduled basis. Their website does not say you can't use it. It says because of their procedure, they can't guarantee it. Big difference.
Very true, and most other oil companies have very similar policies.
但我個人認為新款變更為使用 25~50% organic base 的成分,可以回收, 對環境傷害小,可能是 shelf life 標示2年的主因