I have a '47 9n that has started using more and more coolant. I bush-hogged (4') for 2+ hours and used up 2.5 quarts...and it still runs and doesn't smoke! There are no bubbles in the coolant when running and there is no evidence of flow viewed from the top. This machine has a loader, so work on the front is going to be tough.
Do I start with a thermostat and move onto the water pump?