Sounds like he could just add oil without ever changing it and just swap the filter out occasionally.
If he were to pull into a full service gas station he could say " fill the oil and check the gas"
If he were to pull into a full service gas station he could say " fill the oil and check the gas"
Here's a 25¢ question. Friends $300 car with >300,000 miles. Uses & loses a qt of oil every thousand for many years. He changes the syn. oil & filter every 5000 miles and filters the drain oil. The filtered drain oil is used whenever the engine needs a qt. When the drain oil is all used up he changes the oil and filter. In one point of view the oil is changed every 5000 miles. In another point of view the oil is never changed.