About 50% of the time when installing new coolant hoses and using the standard worm type clamps, about 2 weeks later I will have a very minor leak. It's one of those leaks were it doesn't leak when it's cold, and doesn't leak when it's hot, but leaks during warm up. A quick re-tightening of the clamps will stop it and I am usually good to go from then on, but I was talking to a mechanic about it, and he said those factory spring type clamps won't do that, they keep a constant tension on the hose, even if it shrinks later on.