Does make sense, but.. Some have reported this noise at very low mileage.Too early for a belt to be stretched out so to speak. Others stated it happens when the car hasn't run for a long period. ???
Mine will sometimes rattle if it sits for a couple days without running. Has done this pretty much since new.
Makes me wonder if maybe there is 2 seperate issues with almost identical noises.

 

Here is a Video of the noise - http://www.youtube.com/watch?v=zQGee4D2qtM



Here is the TSB....

GM issued a TSB explaining that the belts where too long and after a few thousand miles the noise would appear. I bought my HHR at 37K and it was there since the purchase day. I could have had the dealer Replace it, But I wasn't driving 40 miles to get it fixed.. Did it myself, got the belt From Advance Auto Parts...


#PIP4716: Sharp Engine Noise At Start Ecotec RPOs - LAF LAP LAT LNF LE5 LE8 LE9 - (Oct 1, 2009)


Subject: Sharp Engine Noise At Start Ecotec RPO's-LAF LAP LAT LNF LE5 LE8 LE9


Models: 2009 Chevrolet Cobalt

With RPO LAP 2.2L, LNF 2.0L

AND

2009 Chevrolet HHR

With RPO LNF 2.0L, LE8 2.2L, LE9 2.4L

AND

2009 Pontiac G5

With RPO LAP 2.2L

AND

2009 Chevrolet Malibu

2009 Pontiac G6

2009 Pontiac Solstice

2009 Saturn Sky

2009 Saturn Aura

2009 Saturn Vue

With RPO LE5 2.4L

AND

2009 Saturn AURA Hybrid

2009 Saturn VUE Hybrid

2009-2010 Chevrolet Malibu Hybrid

With RPO LAT 2.4L

AND

2010 Chevrolet Equinox

2010 GMC Terrain

With RPO LAF 2.4L SIDI

--------------------------------------------------------------------------------

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
In rare instances a technician may comment they hear a short, sharp rattle noise from the front of the engine on start up.

Recommendation/Instructions:
If the noise is from the front accessory drive area, inspect the engine belt. We have seen concerns with engine belts causing a loud ticking type noise. If found, verify power steering pulley outer edge is aligned flush with shaft and repair as needed. If pulley alignment is correct replace the engine belt.

If the noise is still present and is very short and sharp in duration (2-5 seconds) This may be an issue with the cam phasers not parking properly. Once the noise is verified as the phasers, they must be replaced. If the cam phasers are replaced, remove the CMP actuator solenoids to inspect for debris. If debris is found clean and inspect for torn or loose screens and replace if necessary.

Note: If debris is found in the solenoids and phasers change the oil and filter before returning to service, in some instances it may be necessary to change the oil/filter multiple times with a test drive in between each. The filter and solenoids can be inspected afterwards to ensure no additional debris is present.

 

Thanks 2007HHRLT!

That's exactly what I was hoping someone could reference for me (TSB).

My 2009 has just over 48k on it.

I'll be checking that accessory belt

 

Interesting read. If the belt doesn't fix the problem,then there is mention of a possible cam phaser problem. Also noticed that my 2010 SS was not on the list of affected vehicles.

 

Mine hasn't done this for over a year, never changed the belt... Not necessarily the same cause in all instances.

Either that or these belts fix themselves. [/sarcasm]