There are a few different types of radiator clamps. The most common is the band clamp, which uses a screw to tighten or loosen the slotted clamp. A lot of automobile manufacturers use a crimp-style clamp, which requires removing the radiator hose to remove. Another type of clamp commonly used on imports are wire-crimp clamps, which use a variation of the band and crimp clamp and also requires removing the hose. Removing a radiator or a radiator hose will require the removal or repositioning of the radiator hose clamps, and knowing how to do that will help you move the task along.
Position the antifreeze drain bucket beneath the petcock of the radiator and open the petcock by turning it counterclockwise. Always drain the radiator thoroughly before removing radiator hoses. Tighten the petcock after the radiator has drained.
Loosen the screw on the clamp by turning it counterclockwise with a slotted screwdriver or a nut driver for a band clamp style radiator hose clamp. These types of clamps allow you to loosen the band clamp via the screw all the way and allows you to remove the clamp without having to remove the radiator hose. If you're just replacing the clamp, you can install a new clamp in the same fashion and tighten it by turning the screw clockwise until tightened. Band clamp style radiator hose clamps can easily be over-tightened, which will cause the slots in the band clamp to cut into the radiator hose and compromise its durability.
Squeeze the two vertical tabs with a pair of channel locks or pliers on the crimp style radiator hose clamps. The location of the tabs are not always positioned in a remover-friendly spot, however. When the tabs are squeezed, the circle of the clamp that wraps around the hose spreads and allows you to reposition the clamp down lower onto the hose away from the radiator hose to radiator neck junction. Pry the hose off of the junction and then squeeze the tabs again to remove the clamp from the hose.
Loosen the tightening screw on the wire crimp style clamp with a Phillips head screwdriver. This type of clamp will allow you to loosen the clamp, but only to a certain point. You can then reposition the clamp and pry the hose off the junction to remove the clamp from the hose.