Replace the hose. The hose might have lost its flexibility; replacing it will allow it to bend and not blow off under the pressure of the engine. Use the same clamps to attach the hose.
Try replacing the clamp. Also depending on the placement and type of clamp(is it a pinch clamp or the screw kind) it's also possible to go with a smaller clamp. If the small fixes don't seem to work measure the diameter of the hose and purchase a slightly smaller replacement from an auto parts store.
Check it to make sure the hose is fine, and replace clamp, and clamp back together. Make sure to top off any fluids and then check for any possible leaks.
