Alright 
i have a new cooler on its way though i think I've made a mistake but if its feasible to still mount i'd keep it
basically i have
NZXT Phantom Enthusiast USB3.0 Full Tower Case
and i have bought the Corsair Hydro H90 140mm High Performance Liquid CPU Cooler as a new build
I think my rear mount is 120mm only.
if thats the case will i just have to get a different cooler?

i have a new cooler on its way though i think I've made a mistake but if its feasible to still mount i'd keep it
basically i have
NZXT Phantom Enthusiast USB3.0 Full Tower Case
and i have bought the Corsair Hydro H90 140mm High Performance Liquid CPU Cooler as a new build
I think my rear mount is 120mm only.
if thats the case will i just have to get a different cooler?