Engine oil comes in many viscosities (weights) and a variety of base oils. While you should always follow the engine manufacturer’s recommendations for specification category (such as API CJ-4 or Caterpillar ECF-3), that still leaves a wide choice of oils across a range of prices.One of the decisions to be made is whether to use a conventional mineral oil or upgrade to a more expensive semi-synthetic blend or fully synthetic oil.Synthetic defined“A fully synthetic oil is nothing more than a mineral oil that you’ve taken apart and put back together in a controlled way,” explains Jami Melani, the field engineering/heavy-duty
