I recently had a gas leak in my Saturn Ion and they dropped the tank and found the lines needed replaced. So I got new lines and I also knew it was time to get new front tires and an alignment. So I got that done and brought it home and everything was fine. The next day I heard a rattling sound coming the near the back of the car. Took it back and of course as we were driving with the mechanic nothing happened and everything checked out fine. It started again that evening. Not really too load but just something I never heard before. Could it be from the tank sitting differently or alignment? Thanks in advance.
I would look at something with gas tank being dropped.
Gas tank mounting straps/hardware, filler pipe/hardware, fuel pump/electrical wires & clips…etc.
Tester
They may have had to fiddle with the exhaust system. A heat shield may be loose.
Another idea, coincidence. Something has worked its way loose in the trunk. Remove everything from the trunk, including spare tire and jack, and see if that solves the problem.
I took the car back to the shop and after we left it was still making the noise. Took everything out of trunk-still making noise. I drove it around to see if I could pinpoint and it sounded more like the coming from the wheel instead of under the car. Maybe something wrong with brakes because they started to feel weird after we got the car back the first time. The mechanic took off the tire and drums and out came a piece of metal. A part that holds the shoes broke in half and that was the cause. Mechanic had an extra one and fixed it free of charge and now it’s gone!
Good news all around. Thanks for the update!