Good idea. Have you used it during hot weather? I'm thinking tractor might overheat quicker in really dirty conditions. I'll try it. Beats washing radiator fins every day.
I used the same material last summer in a semi permanent fashion. Used tie wraps to secure it to the front of the radiator. I was able to brush off seeds with my hands and blow out stuff at the end of the day. It kept seeds from getting in the radiator fins. The material is designed to not restrict air flow, hence its use in home heating systems. My plan this summer is to pull out the screen and whack it on the tire as needed. The angle iron at the bottom is not needed and was removed, moving the air intake filter makes access much easier.
Some follow up on this mod. Used the tractor for about 20 hours mowing this summer and only needed to clean the filter every few hours. Usually when I was taking a break or adding fuel. A great improvement over the factory set up. Moving the air filter also worked well and made cleaning the filter easier.
Furnace filter sounds like a great idea. I'm going to try that on my tractor as soon as I get a chance. When I schlepp composting leaves with the FEL, most of it seems to end up plastered to the radiator and I need to shop vac it.
See my final post (today), on the Y385T engine forum to see what a difference a clean radiator made in my case.