When you took off the IACV some coolant leaked out from the lines right? Unhook the same line from the IACV and let some run out then reconnect. But first i would clean the IACV screen. And when you drain it leave the radiator cap open so theres no pressure in the lines.
PLEASE MAKE SURE ENGINE IS NOT ON AND THAT THE CAR HAS HAD TIME TO COOL DOWN!!!