Before adding oil, you need to buy it in a store, pay attention to the oil cooler. Be very careful in choosing, find out which oil used to be used in the car or what manufacturers advise. If you just bought a car, then we advise you to completely change the oil. Also completely drain the oil if you move from one species to another. Try not to mix the oils of different manufacturers, but if it has already happened, then keep in mind that in the new mixture of the added oil there should be no more than fifteen percent. And after some time, try to return to the product used earlier. Mix synthetic oils harmless.