[rx4ur7]

Yes, what kind of radiator is it? 1 800 radiator or Performance Radiators are 99% correct except for not being aluminum. Fit well, just aren't as effective as Al unless you get something much bigger. And then there is the cost in that much weight in the front of the car.
Just a point, to make a copper core radiator as effective as an AL you need a lot more core. And they weight a lot more than the Al. I haven't seen that copper cores in the FC or FD in Tucson`work very well.

BTW Thread is 12mm x 1.25

It is a ground switch, water touching it completes the ground circuit.
This is why rubber mounts are not recommended, unless you use a jump wire from one of the rad mount bolts to chassis.