Boyfriend has a 16 Kia Optima with a 2.4 we’ve been together five years and I’ve changed the oil ever since we’ve been together. Last two oil changes were about 5 to 6000 miles each and was using Pennzoil platinum full synthetic 5w30. Has no leaks but last oil change was 2 quarts low. And the oil change before that was 1 quart low inspected and found no leaks. Has 77 or 78,000 miles. Switched to Pennzoil full synthetic high mileage 5w20 because they had no 5w30 hope to slow down the oil consumption, but the oil came out did not look good. He has 9 months left till it’s paid off and don’t wanna buy a car because we want to buy a house. I don’t think it started burning oil till the last two oil changes that I can remember.