A loud exhaust noise, like a roaring sound from underneath
When the usual quiet ticking of the engine turns into a loud roar from under the car, it's not just annoying to those around you, but it's also a sign that the exhaust system has lost its seal. You shouldn't ignore this symptom, as toxic gases can get into the car.
Likely causes — most common first
Damage to the exhaust system's flex pipe
The flex pipe is a flexible metal element that reduces engine vibrations. Due to constant stress and corrosion, it can tear, and gases start escaping before they reach the silencer, creating a loud noise.
A hole in the silencer or resonator
The metal in the exhaust system thins out over time due to moisture, road salt, and high temperatures. Holes form in the silencer or resonator, which is an extra sound-muffling chamber, and this is what causes the loud humming noise.
Leaks in the connections and worn-out clamps
The exhaust system's pipes are connected with clamps and gaskets. Over time, these connections loosen or wear out, creating gaps that allow the exhaust to hiss or roar.
A broken or worn-out exhaust mount
The rubber mounts hold the exhaust system to the car body. When these mounts break or stretch, the pipes sag, hit the body, and can put strain on other connections in the system.
