Sway bar links are a good bet. Same for strut/shock mounts.
1991 Toyota Pickup 22R-E 2.4 I4/5 speed
1990 Toyota Cressida 7M-GE 3.0 I6/5-speed manual
mechanic, carpenter, stagehand, rigger, and know-it-all smartass
"You don't get to judge me for how I fix what you break"
Way back in history I once bought a set of rims and had the tire shop install them. My car started rattling as if it had a load of aluminum extension ladders on a roof rack. Turned out that the way the wheels fit, with the lug nuts fully tightened, somehow allowed the drums to to slide along the studs and bang between the hub and wheel.
Well, its all OEM, and spraying silicone lube on bushings and other rubber parts didn't help the isolate it. When I rotate the tires, I'll take another look, but it seems to have quieted down on its own.
I got used to it, or the mysterious front end noise of the HHR is drowning it out. That gets worse in the cold. It wasn't mentioned during the annual inspection, but I take it to a Chevy place and they know about the mysterious noises.
The gas filler is there, and the filler neck might loose. Same with the battery. It could have simply been something in the back storage area, and I accidently fixed the noise moving stuff around in the car.
Do you have drums in the rear?. I had a similar problem with "clunking" i guess you would say. I had replaced the rear shoes and drum on my civic. A few days later I began to hear this clunking, only after turns at low speeds, and only sometimes. I ended up taking the drum back apart, but to my surprise, it was full with sand. Enough sand to fill the small of your palm. Not sure how it got in-there, but cleaned it our with a air hose, checked for scoring, put it together, and it has not happened since.
when I had my windshield replaced they said I have a lot of dirt under the grill work below the glass and I don't live on dirt roads but I did drive on some last June and apparently it gets in there and doesn't wash out. I had it pouring out of my hub caps after that couple of miles of dirt road driving. that dirt can get in the darndest places.