I originally had my o2 sensor too close to the under body of the car and it would rub, problem is it wore away the coating on the wires. Now we put some silicone type grease on them and it held up for some time but when I went through some water it blew the fuse again. What can I use to protect those wires? Would some epoxy or something like that be good to use? Would it trap moisture or anything? Any products/brands you guys recommend?

 

Only way to protect bare wire is heat shrink. Unfortunately, you will need to cut the wire, insert heat shrink, solder wire back together, and apply heat from hairdryer/heat gun/lighter to shrink and watch it shrink to half its original size and waterproof seal the joint.

Other way: Electrical tape. I wouldnt necessarily recommend this option though.