I have a Core V21 and I've been trying to install a Corsair H100i v2 (same as the GTX one) in my case, yet no matter the location of the radiator (minus the front, as I have the 200mm fan there) I can't get a side panel to fit on properly. It seems like the screws/washers that came with the cooler and are used to hold it in the brackets are too high and the side panel presses down on them when I try to slide it on.
I've tried adjusting which bracket holes keep the cooler in place and installing it fan-side up but nothing seems to work. Any ideas?