Can two lubricants be mixed together in the same engine?

It is not recommended, but if for some reason different oils must be mixed (to fill the tank for instance), it is important to follow certain recommendations.

It is a good idea to use an oil with the same level of quality as the one that is currently being used in the vehicle and, if possible, from the same manufacturer. Additionally, during the next oil change, it is a good idea to replace the oil filter with a new one.