Hi, when starting my daughter's 2006 cobalt SS there is this rather load knocking/clicking sound coming from inside the dashboard. It knocks 7 or so times and always does this. The engine doesn't have to be running for this to happen.
Any ideas?

 

Hello dilogdp,

The following may be behind the knocking noise you described: the vehicle needs higher gas octane rating, has a clogged air filter, or the timing is off (pulled from Oil Filter Guide - Oil Life Monitoring - Dirty Oil Filter | ACDelco and should not be considered an official GM diagnosis as the site is not maintained by GM). I hope you receive more helpful feedback from the community, and if I can check into warranty/recall information on your daughter's Cobalt please send me the last 8 digits of the vehicle's VIN.

All the best,
Sarah
GM Customer Service

 

My mom's 06 LS has the same thing going on. Drop the glove box and listen again to see if you can pinpoint the location. On her car it appears to be coming from the airbag module area...going to take it in for a looksee soon.

 

The clicking is the door in your airbox for the recirculation function on your HVAC system. The actuator is bad and the clicking is the vent door trying to open. To test and make sire its your problem, turn the ac off, but the blower on max, and the selector on the vent facing you (furthest left position). Turn the key on, and hit the recirculate button while its clicking. If it stops, you know its your problem. Good luck!