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Loud Exhaust Noise

A suddenly louder, rumbling or blowing exhaust usually means a hole, a broken joint or a failed gasket somewhere in the exhaust system.

Normal risk

Have it checked soon. A leak before the cabin can let exhaust fumes in, which is dangerous.

Short answer · Why is my exhaust suddenly so loud?

Exhaust systems rust from the inside, and joints, gaskets and flexible sections wear. When a hole opens, the gas escapes before the silencer and the car gets louder, often with a blowing or puffing sound. Leaks near the front can also upset the oxygen sensor readings.

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Safe checks you can do

  1. Listen at cold startA puffing or ticking sound near the engine or under the car points to the leak.
  2. Look under the carBlack soot marks around joints show where gas escapes.Never touch the exhaust after driving; it stays very hot.
  3. Notice any smell insideAn exhaust smell in the cabin is a reason to stop driving.

Questions that narrow it down

  1. Is it louder under acceleration?Typical of a hole or broken joint.
  2. Is the engine light on?A leak before the oxygen sensor can cause mixture codes.
  3. Can you smell exhaust in the car?Get it fixed before driving further.

Possible causes

Listed without ranking. Use the questions above to see which ones fit your car.

  1. Rusted silencer or pipeHoles form over time.
  2. Failed flexible sectionThe braided joint near the engine cracks.
  3. Blown gasketBetween manifold and pipe or at a flange.
  4. Broken hangerThe system hangs low and can crack.
  5. Cracked manifoldTicks or blows near the engine.

Questions about Loud Exhaust Noise

Is a loud exhaust illegal?

Many countries have noise limits, and a leaking exhaust can fail an inspection.

Can an exhaust leak affect fuel economy?

A leak before the oxygen sensor can make the engine run richer.