I have a front end rattle in my wife's 07 HHR. I have replaced all the usual suspects, sway bar links and bushings, lower control arms with Moog rear bushings, Monroe Quick Struts and rear shocks. I also secured the bumper cover to the bumper. I also tightened up the condenser brackets to the condenser. There is still a rattle like I've done nothing. What else could cause this same kind of rattle? The sound is coming from engine bay area.
I am out ideas. Does anybody know what else it could be?

 

Under what conditions does it Rattle? Does it diminish at any time.
Have you looked at the Hood adjustment?
Put your hand under the front and lift up and down without using the release latch to see if there is any play. Also Lube the latch.
Lube all the rubber bushings under the hood as well. I use silicone grease.
Check the Intake Air Box to see if you can get a hint of noise.

Silverfox

 

We have 300 feet of rough gravel driveway. It rattle consistently there and whenever there sharp seam in the pavement not so much with pot holes.
The hood is tight. The air box is tight, it doesn't move easily. I can't find anything loose.
I jacked up the engine to check motor mount play, all seam good. I've pulled, pushed and pried on what I can get to. I don't have lift. Just jacks and stands, so there is no weight on the suspension.

 

Well when in desperation you start looking at every and anything. It's a matter of Elimination.
Do you have wheel covers ie: LS or 1LT
Carefully check the tightness of all the wheel cover plastic bolts.
They can cause the wheel cover too make noise on the steel wheel if loose.
Carefully torque them.all... they do not require too much.
Or take them all off to test this first.
If you have a torque wrench you should check your wheel bolts at 100 lbs.while the covers are off.
SF

 

This 07 HHR has alloy wheels. No wheel cover rattles here. Thanks for the idea. Let me give a little back ground on this car. We bought it used fairly cheep. It ran and drove okay but was not cleaned or maintained. It's had a hoast of small issues. I've gone over this car from front to back repairing different things. This is the second, third or fourth round trying to fix the rattle in the front end. IDK. The first go round I did use Detroit Axle parts because of cost. There has been at least two of everything but the struts. The second go round I replace with Moog parts. Whenever new parts are installed the sound has changed but not gone away. This time when I changed the lower control arms, struts and tie rod ends the rattle was as ever. It was there as soon as I backed it out to get there alignment. The steering was tight but the rattle was still there. Although the rattle was all but gone when driving on pavement. Now a week later it's as bad as ever. I've done front and rear brakes so the thread about the cracked rotor doesn't apply this time. Again thanks for advise. Still stumped.

 

Have a look at the centre transmission mount, the intermediate steering shaft, check torque on the steering rack bolts , I’ve not heard your rattling but something I’ve encountered was the fog light hole covers, on my LS also a 2007. It’s a matter of elimination, all the plastic button fasteners on the splash guards, front bumper lip, the bumper cover clips by the headlights, even the headlights themselves, a loose bolt can drive you nuts! As my OCD does!

 

I've already been through the push pins when I secured the bumper cover. It has the fog light option but I will check them and the rest.
Thanks

 

I forgot the exhaust manifold heat shield, that back hole , I use a couple of SS washers to sandwich it into silence! And the ever elusive air cleaner box bracket, it can crack and rattle without detection.

 

I checked the exhaust cover and the breather brackets last night. The flex joint and exhaust hangers seams to be okay as well. I replaced a cracked exhaust manifold last spring. It didn't affect the rattle. The rattle seams like something heavy and almost sloppy loose, like rocking back and forth or up and down. I will check the trans mount and rack bolts. That the area the sound seams to be coming from.
Thanks.

 

I forgot the Intermediate steering shaft and the Steering column

With HHR sitting parked on the flat ... motor off,...steering wheel centered .
Turn steering wheel back and forth against resistance to see if you hear any noise. It would be like slack in the system.

That is How the Chevy Tech checked mine as a start point.
There was noise.
They wanted to replace those two parts and also possibly the power steering motor.

SF