Is your oil-cooled Milwaukee Eight overheating? It’s not something I’ve experienced but then I don’t live in a city or the Mojave desert, in which case I might have been more welcoming of news that you can now get a fan to cool the oil-cooler. I’m guessing that it will live inboard of the cooler, for aesthetic reasons.
It is triggered by the engine temp and vehicle speed sensors to keep things running cool, and is available from your Zodiac dealer.