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Old 06-20-2011, 12:33 PM
Join Date: Mar 2011
Posts: 1
Knocking Sound Coming from Cobalt when Started

It's a 2006 Cobalt LT @ about 80k miles. Bought used about 4 months ago, and this started happening in the last week.

It sounds like it's coming from under the dash on the passenger side.. Happens about 80% of the time I start the car. I've uploaded a video of it happening

Would be great if someone could help me out.
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Old 06-20-2011, 01:03 PM
06BaltLS's Avatar
Join Date: Feb 2011
Location: JC, MO
Posts: 505
Could be a wheel bearing, strut, a arm, anything having to do with that. Prolly doesn't help much but its all I could think it'd be

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Old 07-04-2011, 12:56 PM
Join Date: Mar 2011
Posts: 8
I to am having this problem! Would be great help if anyone knew anything.
Old 11-18-2011, 10:56 AM
Join Date: Nov 2011
Posts: 2
Hey I have to same noise! Can you please tell me if you ever found out what it was????
Old 11-18-2011, 11:58 AM
Jimbug's Avatar
Forum Regular
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Posts: 129
Does the sound change if you go from heat to AC?
Old 11-18-2011, 12:10 PM
ChevyCustSvc's Avatar
Chevy Customer Service Premium MemberExpert
Join Date: Nov 2010
Location: Detroit, Michigan USA
Posts: 794
If those who have experienced this concern would please private message me with more details, I'd be happy to look into it further.

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Old 11-19-2011, 05:09 PM
Get Out The Sawzall
Staff AlumniCobalt Master
Join Date: Apr 2010
Location: Sewickley, Pa
Posts: 1,856
This is the recirculating air motor and flap and is located under the glovebox. Cheep Chinese parts that have broken on thousands of GM delta series vehicles. Some have fixed this issue themselves be rotating the motor gear 180*. Others have a simple fix, the flap (with recirc off) opens (comes forward) and just keeps banging the plastic, with recirc on it opens and its all good. The stealership will charge you about 200 bucks in parts and labor to fix this flaw and since your out of warranty, I would suggest to try the recirc button if you have one that works, try turning the gear or others have just ripped the plastic flap out.
Old 11-19-2011, 08:47 PM
Get Out The Sawzall
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Old 11-20-2011, 11:58 AM
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Join Date: Oct 2011
Location: Magnetic Hill, New-Brunswick
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Looks like you might have a broken cog on that flap mechanism. Remember recirculate button only works on first two settings according to manual anyways. When it is set to floor or defrost front windshield it will not activate.
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Old 12-16-2011, 12:13 AM
Join Date: Dec 2011
Posts: 1
My cobalts making the same noise!

I'm doing some repairs on my cobalt this weekend and wanted to know if you figured out what the problem was? I am experiencing the same noise lasting the same duration as posted in your video. The noise is EXACTLY like and its been driving me nuts!

---------- Post added at 11:13 PM ---------- Previous post was at 11:11 PM ----------

Did you find anything out? My 08 Cobalt is making the SAME noise!
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