How to Stop a Furnace From Oil Canning

Turn on your furnace and pay attention to which ducts, or pipes, are knocking or shaking, leading to the oil-canning noise. Make a note of which ducts are the area of concern.

Tap around the connection site, gently, with a hammer. When the connection site has a wooden wall against metal connection, it is a common area to hear the noise. Making small dents along the duct's connection area will tighten the connection and prevent it from being able to wobble around as much. This can also happen with a concrete wall.

Disconnect the pipes, or ducts, at the connection site and insert a rubber gasket, or rubber pads, between the metal and the wall. When the pipes and ducts vibrate, the rubber will reduce the noise and possibly eliminate it. The disconnection procedure may vary depending on how the pipes or ducts are connected. It may be as simple as using a screwdriver and unscrewing it, or they may have a sealant holding the connections together, which would require a utility knife to cut through the sealant to loosen it.