If your car suddenly sounds like a hot rod, something in the exhaust system has broken or come loose. The good news: it's rarely an immediate safety issue. The bad news: it can quickly turn into a fine and a failed inspection.
Drive home but get it diagnosed within a few days. A leak before the oxygen sensors makes the engine run incorrectly, which can damage the catalytic converter (a $1,000+ part) or trigger limp mode.
Rust eats through exhaust pipes from the inside out. A pinhole grows quickly into a major leak. Sudden change in noise usually means a section finally gave way. Parts: $30-300 · Labor: $100-500 · Shop recommended
See What To Check →The internal baffles in the muffler rust and disintegrate, or the muffler shell rusts through. Sudden loud and lower-pitched than usual. Parts: $50-400 · Labor: $80-300 · Shop recommended
See What To Check →The catalyst substrate inside the converter can break apart and rattle, then suddenly the noise level jumps. Usually paired with P0420 or P0430 codes. Parts: $300-1,500 · Labor: $150-400 · Shop recommended
View P0420 Diagnosis →Exhaust manifolds crack from heat cycling, especially on V6 and V8 engines. Often makes a tick or chuff that's loudest cold and quiets as the metal expands. Parts: $100-600 · Labor: $200-800 · Shop recommended
See What To Check →A rubber hanger broke and the pipe is hanging lower than usual, or a clamp came loose at a joint. The cheapest fix - sometimes a $5 part. Parts: $5-30 · Labor: $30-150 · DIY easy
See What To Check →Tell us when the noise changed (after a bump, after a cold snap, gradually getting louder) and we'll match the likely cause for free.
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If your scan tool is showing one of these codes, that's your starting point. Click any code for the full diagnosis, common causes, and repair costs.
For short distances, usually yes. The bigger concerns are: carbon monoxide leaking into the cabin (open windows and check it gets fixed soon), the engine running poorly because of a leak before the O2 sensor, and getting a ticket. Don't drive long-distance with it.
Yes, if it's before the oxygen sensors. The leak draws air into the exhaust, fooling the sensors into reading lean. The computer adds more fuel, which can foul plugs and damage the catalytic converter. Holes after the cat are noise-only.
Usually a piece of rusted-through metal finally let go. Exhaust components corrode for years before failing all at once. A cold snap, a bump, or just one more heat cycle pushes a weak spot past breaking. The repair is usually straightforward.
A loose hanger or clamp: $30-100. A small pipe weld or section repair: $80-300. New muffler installed: $150-500. A cracked exhaust manifold: $400-1,200. A failed catalytic converter: $500-2,000+ depending on the car.