Engine Oil and Fluid Recommendation for Jeep (USA) Changing the engine oil in a car is an important step in caring for it. There comes a time when you need to change the engine oil in your car. But such a process as the selection of engine oil is a serious problem for you. A lot of questions instantly arise: which oil is suitable, which brand is better, when it needs to be changed, where it is more reliable to replace, etc. Only Oiler will help you competently understand all the issues related to engine oil that haunt you.