Loud and vibration sounds underneath hood

Hi and thanks for using 2CarPros.

Does this only happen when you are stopped or does it happen when you are still moving and apply the brakes? Also, pay attention to the RPM's when you are stopped and it's making the noise and let me know what they are.

If possible, upload the sound when it happens so I can hear it.

Let me know.

Joe

Could the sound be a heat shield that is rattling?

Welcome back:
I don't feel the motor mounts would be that bad. However, they sit on rubber. I guess if the rubber has deteriorated totally, you may feel a vibration from the engine, but I don't think you would hear it. Also, any of the belt driven components could make a grinding noise if a bearing has gone bad. You could remove the serpentine belt and start the engine for a few seconds to see if the noise is gone. If it is, spin all of the components to see if one feels bad. Since it only is heard when you stop, to me it seems like something is vibrating at low RPM's. If you could record the sound and upload it for me, I may be able to identify it.

Let me know what you find,

Joe

Hi and welcome back:

I listened to it a few times. I do hear a rattling but it is very hard to tell what it is. Based on experience, it sounds like either the insides of the catalytic converter may have come loose and vibrate, or something in the exhaust. Please keep in mind, I have even heard AC compressors, fans and other things which sound similar.

When the vehicle is stopped, is there anything that causes the sound to change? For example, if you are using the defroster and turn it off, does the sound change?

Here is what I suggest, park the vehicle on a level surface and secure it from moving. Take a rubber mallet and tap on the exhaust system to see if you can recreate the sound.

If you find nothing, have a helper start the car and place it in gear so the sound occurs. Open the hood and see if you can tell aprox where the sound is coming from.

Try that and let me know what you find.

Joe