Scotty,
My parents gifted me a 2000 Dodge Durango last month. It's a V8, automatic trans with about 107k miles.
Overall it runs fine but It's been losing coolant for at least a year. No white smoke, clean oil and clean coolant. I also don't see any leaks on the pavement either. Despite that, it's gone through about half a gallon of coolant over the last year (about 4k miles).
Any hints on what to check?
Do a pressure test on the cooling system to make sure and im sure you will find your answer.
Change the radiator cap with a new one & check if that fixes it.
If it continues to lose coolant, watch scotty’s video on how to fix an overheating car.