Back some time ago, one of the big 3 auto makers was plagued with rattles in one of it's vehicle line.
No dealer could figure out exactly where the noise was coming from until someone discovered a soda bottle in the frame or an enclosed panel.
This was determined not to be a fluke as every so many vehicles had the same problem, and it was later determined to be deliberately done, by perhaps, a disgruntled auto worker who was too lazy to seek a trash can or maybe an act of industrial sabotage.
More-than-likely this is not the cause of your rattle/bang-or is it?
Catalytic converters do not rattle. If it does it will need to be replaced as it may block the exhaust. Loose heat shield?
They could squeak, rattle, bang , clunk.....
A rattle in the right front fender of a Toyota Camry may indicate that you need a wheel alignment. It could also point to a problem with your struts.
Could be a noisy ac compressor that is low on freon.
There could be hundreds of different things that could rattle. Give us more details. A common rattle is from the catalytic converter. The inside breaks and pieces get into the exhaust and rattle.
it could be lose bolts, screws, brake pads or disks.
Might be the catalytic converter. The inside can break and rattle around in the converter or muffler. If you can raise the car enough hit the converter with your fist you should be able to hear the rattle if that is the problem. Might be the shield around the converter. The top half comes loose on one end and then rattles. Although answer 1 is correct, it only relates to one possible cause, and just because you checked and tightened all the "obvious" parts does not mean the the rattle has to go away. First, one of the "non" obvious parts that you could not see, or simply overlooked, may still be loose. Also, rattles are not necessarily the result of a loose nut, bolt, or screw. It is also possible that a stone, loose tool, or any foreign object could be inside some cavity in the auto body, and the shaking that occurs on rough driving surfaces could cause the movement resulting in the rattle.j3h.
Ultraviolet radiation (part of sunlight).
There are a scad-zillion different kind of noises that it could be making. You need to BClear. Knock, rattle, chirp, bang, tick, squeal, chatter etc. Description and when it occurs is important to know.
Possibly a wheel bearing
you may have a loose clamp holding it. You could have a rock in it.
High water pressure could be the reason for pipes to rattle when you turn on the outside sprinklers. You may need to have a reducer valve installed.