That sucks.
Gotta say I am not impressed with what I am seeing/hearing regarding Champion. Whilst they do continually honor their warranty claims and pay for the shipping, my mate is on his third rad already in the space of only a few years. At what point does your labor and downtime outstrip the cheapness of these rads. Does appear to be one of those gets what yer pay for situations.
BTW my mate was able to get them to react pretty quickly a week ago for his latest failure. Also the first one they sent got damaged, he said their their packaging sucks, but he got them to overnight a replacement better packaged so it sounds like he was able to get quick response from them.
Cheers
Nobby