Exhaust, fuel & emissions

Muffler has rusted through with a hole

A rusted-through hole in the muffler lets exhaust escape before it's fully quieted, causing a louder, often deeper exhaust note, and it will only get worse (and can spread) over time.

Difficulty
Moderate
Time
30–90 minutes for a patch; longer for full replacement
DIY cost
$15–$60
Pro cost
$150–$500

Symptoms

  • Noticeably louder, sometimes deeper-sounding exhaust
  • Visible rust hole or flaking metal on the muffler when inspected
  • Sound may vary with acceleration
  • Possible visible rust streaks or scaling on the muffler body

Likely causes

  • CommonAge and corrosion from moisture cyclingMufflers collect condensation inside and rust from the inside out over years of use.
  • CommonRoad salt exposureSalt used for winter roads accelerates rust on the underside of the exhaust system.
  • PossibleFrequent short trips preventing full dryingShort drives don't get the exhaust hot enough for long enough to evaporate internal condensation.
  • Less commonPhysical impact damage (curb, road debris)A dent or scrape can weaken metal that later rusts through faster at that spot.

What to do

  1. Look underneath for a hole, rust-through, or a section that looks thin, flaky, or scaled.
  2. Note how loud and where the noise is coming from to help a shop find it quickly.
  3. Get a repair quote comparing a patch/clamp repair versus a full muffler replacement.
  4. A temporary exhaust repair tape or clamp kit can quiet a small hole short-term but isn't a permanent fix.
  5. Have the muffler replaced or professionally welded once you can get it to a shop.
  6. Consider a stainless steel replacement if you live somewhere with heavy road salt, since it resists rust much longer.

Tools and parts

  • Flashlight
Muffler repair clamp/patch kitSearch: “muffler repair clamp kit”
Replacement mufflerSearch: “muffler for [year make model]”

When to call a pro

A muffler shop can weld in a proper repair or replacement quickly and confirm there isn't a second weak spot nearby.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.