A friend of mine drives truck for Schneider and gave me a gallon of their 15-40 oil. It is a very nondescript plastic jug with a label that states that it is not to be used in gas powered engines. The only vehicle of mine that I would consider running it in would be my Citroen 2CV which has no cat, is aircooled, and is over 20 years old. Would I have any issues with this? Or does anybody know about this oil?