If your exhaust is blowing a gale—sounding like a Spitfire or an old crop-sprayer—it’s usually down to a hole that’s developed due to corrosion or decay over time, or where two pieces of the system have separated at their joint.As well as loud, thundering noises, other tell-tale sounds of an ailing exhaust are hissing (cracks or leaks), chugging (blockages), and rattling (the exhaust is loose or misaligned).