Skip the auto shop - Our mechanics make house calls

Q: Loud noise from underneath car.

asked by on

Noise coming from underneath the car. It is so loud that attendants at a drive through window found it hard to hear my order. It's been doing it for a while, but the car runs fine.

A: Hearing any noise coming from your car can ...

Hearing any noise coming from your car can be startling, but it can be especially so when that noise is so loud others cannot hear you! Though the information provided is a bit limited, my experience tells me that the noise you may be hearing may be due to a leak in your exhaust system.

As vehicles age their components will naturally wear out and when you add the extreme heat of the engine to the equation, it is only a matter of time until one of those parts completely fails. Now if your vehicle seems to just sound louder in general, then it is likely your car either developed a hole somewhere in the exhaust system or the exhaust gasket itself has failed. When a failure happens, it will allow exhaust gases to prematurely escape the engine bay by bypassing the muffler. This is what you are hearing when you are aware that your vehicle sounds louder.

However, if instead you hear a clanking noise, such as a couple of quarters in a coffee can being occasionally shook around, then it is possible the material inside a component known as the catalytic converter, or even your car's muffler itself, is failing and breaking down. When this happens the materials inside these components tend to break off in chunks and sit at the bottom of the muffler/catalytic converter and bounce around. This could also be the noise you and others are hearing.

As you can see, without actually hearing the noise it is a bit difficult to narrow down the issue to one diagnosis. Your best bet would be to next contact a certified mobile mechanic to not only use their mechanic’s ear to narrow down what you are hearing, but also inspect your entire vehicle for safety.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Engine pings

Engine ping is usually caused by bad spark plugs. Typically the spark plugs become worn out and do not detonate the cylinder at the proper time. I would recommend having a tune up performed by a technician. Spark plugs and...

Q: I put the wrong key in my car and a few weeks later my car just shut down and it will not start I believe it's the computer but...

Hi there. What had happened is the wrong key set the security to the vehicle. This is to prevent the vehicle from starting with the wrong keys. Try removing the battery cables (+) and (-) for 13 minutes. During that...

Q: Electronics in car stopped functioning.

Hello, when you jump the vehicle, a power surge may have open some fuses. Fuses protect the electrical circuits and components from damage. The fuses have an amperage ratings, a power surge would put the fuse pass it rating and...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.