2001 Other Mercury Models Rattling/Squeaking noise from the

Hi, my car is 2001 Grand Marquis.
The noise appeared once several months ago and then disappeared. It has been quite loud for several weeks.
The noise is generated when 1) the car is turning left or right, whether still or moving; 2) the car is moving on a bumpy surface; 3) the car is being bounced up and down by hand at the left side of the hood while it's still, sometimes there is a little noise when the driver leaves the car. When the car is runing straight on a smooth road, there is no noise at all.

I'm a new driver. I am going to use a stick or something to help determining the position of the noise, but it will be really helpful if I could get any advice and I truly appreciate it. Thanks for your time!