很有趣的一個問題,查了查,覺得有些道理

出處: http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1253274

Once ran in the engine the oil has to deal with contamination, combustion byproducts and moisture. All of these deplete the additives in the oil over timed.

In storage oil should be good for 5 or so years depending on storage temperatures and the types of additives used. The oil itself never goes bad and can be recycled and reused indefinitely following proper purification process such as hydroprocessing.


In the engine the oil doesn't "go bad" It becomes contaminated and the additives that fight contamination and acid build up and act as antiwear and friction modifiers wear out causing the oil to be less effective as a lubricant and corrosion inhibitor.