BigSwede

Once the rust chemical reaction starts it will continue as long as it has access to air and water. Driving the rig in the rain or even humid conditions with condensation is enough to keep it going, although it's certainly not as bad as driving it...

I'd hit it with Fluid Film, stops the rust from progressing. You don't want a rubberized coating over rust, it will keep going (dunno what your Amish guy is using).

After you filled and let it run for a minute, did you pull your oil dipstick? If not, go pull it and see if the oil is milky. If it is, you burned a head gasket. If not, you might be okay. What is concerning is you replaced the radiator and...

Yes. There aren't any other wires or sensors at the front wheel in any case.

I had headlight system warnings when I had broken front wheel sensor wire.