The hose comes off and there is a clean line cut into it, right under where the clamp sat, sometimes through the wall and sometimes most of the way. The joint was not leaking before it was disturbed. This is not a fault in the hose; it is what a clamp edge does to a soft material under sustained load.
Silicone is resilient, but it is not hard. It cold-flows under a point load, and the edge of a clamp band is a line load. Given enough tension, heat cycles and vibration, that edge works its way into the wall the way a wire cuts through cheese.
The cut is a stress concentration. Once the edge has started into the surface, every pressure cycle opens it slightly further, and the material cannot recover because the clamp is still holding the edge in the groove it has made. That is why the damage looks machined rather than torn.
It also explains why the failure appears where nothing seems to be moving. The hose did not need to move; the clamp edge stayed in one place while the wall crept into it under tension and heat, which is a slow process that looks sudden when the wall finally gives way.
A narrow band concentrates the same clamping force onto a smaller area. A wide band spreads it. That is the single most useful thing to understand about clamp choice on silicone: the band has to be wide enough that the load on the rubber stays below the point where it cold-flows.
Look at the width of the band against the wall of the hose. A band that is narrow relative to the wall, combined with a tight installation, is a candidate for this failure. So is a band with a stamped or slotted edge, which presents a line of small teeth instead of a smooth edge.
The clamp should sit on the hose behind the bead, not on the bead itself. Sitting on the bead puts the band over a convex ridge, so load concentrates on top of the ridge and the edges dig in on both sides. The result is a cut on the inner edge, usually on the side facing the pipe end.
The same happens at a step where two pipes of different diameter meet, or where a weld seam sits under the clamp. Any raised feature under the band becomes a line of concentrated load. Move the clamp onto plain cylindrical hose and the problem usually disappears.
A clamp cut runs around the hose, exactly under the band, with clean edges. A pressure split runs along the hose, usually starting at a bend or a heat-damaged area, with ragged edges and often a bulge. A cut from installation is a nick at the very end of the hose where it was pushed over a sharp pipe edge.
Those three patterns point at three different fixes. Circumferential damage under the band means clamp selection and tension. Longitudinal damage means pressure, heat or a tight bend radius. A nick at the end means the pipe needs deburring and the hose needs lubricant during assembly.
When you replace the hose, replace the clamp as well. A clamp that has cut one hose has a damaged edge and will do the same to the next. Choose a band wide enough for the wall, with a smooth inner face and a controlled tightening action rather than a worm drive that ratchets past the tension you wanted.
Then check what sits under the band. A rough weld, a burr on a bead or a step in the pipe will cut the new hose in the same place. Where the joint runs close to a hot component and the hose has already been softened by heat, a heavier wall is the answer rather than a tighter clamp; the performance silicone hose range covers the common coupler sizes, and heavy duty silicone tubes are the option where the joint sees sustained heat and movement.
