Here we can see how I secured the long 1/4-20 bolt I used to hold the fan. Bolt head is on the radiator side of the mount (I checked to make sure it clears), a nut secures the bolt to the mount, the nylon spacer is visible and if you have young eyes you might just be able to see the window foam sealing the fan. There is barely a gap to seal.

fan spacer.jpg