I ran one of those style switches right up until Ohio mud and water got in it
American Volt sells a two pole switch on Amazon with a MUCH better two piece design. I'm running one and love it.
The bitch with the single pole design is eventually water gets in them, and you're SOL when your fan quits. Or worse, they get old and separate and you have a coolant sprayer. The two piece one is a solid brass plug, so worst case, you're just changing the switch and don't lose a drop when you do.
American Volt Electric Radiator Fan Power Thermostat Switch Temperature Sensor Thread-in Brass Probe (3/8" NPT, 190'F On - 175'F Off)
https://www.amazon.com/dp/B07NCLCKS7/ref=cm_sw_r_cp_apa_i_juO0DbRYK5E9T