Ignoramus16841 wrote:

It would not be very safe to put it on a pump that sits in a coolant
sump next to water level.
Well, put long wires on the motor end, clean the area with solvent and
glop liberally with RTV to seal the connections against moisture. Then,
mount the commodity cap in a safe location.

HVAC contractor supply outfits have these very cheap, but they may need
you to show business identification before they will sell to you.

Jon