raise the hood on an M series, look at the bottom of the hood. They put self-stick foam on the hood, so when you close it, the foam contacts the top of the radiator. There's usually also some along the sides of the hood and on some of em there's foam around the cores themselves (radiator usually). Kubota uses different terminlogy for the foam, some tractors they call them pads others they call them tape, others who knows. Jinglish. One you learn Jinglish, you'll better understand "Kubota". Every tech that came into our shop, during the first week or so we'd be talking about different stuff and I'd try to burn into their brains about "Jinglish". A few of them listened. Others just laughed. One of them I remember well, he had an issue with a standard L that wouldn't start. He asked my my thoughts, I told him you might look at the delay reray (that's what the book calls it). Sure enough, ordered a new delay reray and it solved the issue. Bad part is, on the r/o, he keyed it in as such "Replaced reray". Part description was also exactly that "delay reray). Customer was thrilled about that.
Have had some MX's show up that would run hotter than normal, all the foam missing off of the hood. Put it back on, heating issues resolved. Damaged hoods were an issue as well in that sense. They wont' seal very well around the cores.
my car has some plastic baffling around the outside of the IC and the radiator of course part of that reason is airflow due to forward travel. Tractors don't have a fast enough forward travel to generate enough airflow to make any difference, so the fan does all the work.