Update 2011.09.16: At this point I'm quite comfortable with saying that this issue was definitely related to the passenger side hatch damper. The issue persisted after spot welds were reinforced, and ceased after the dampers were replaced.
I am now also keeping this updated in my blog as well @ 2008 Subaru Impreza WRX STi Hatch - "theNoise" (Broken welds = Squeak)
Car: 2008 Impreza WRX STi
Problem: Broken welds on roof support near hatch opening causing metal on metal squeaking over bumps or in turns.
Update 2011.08.27; Could this have been misdiagnosed??? <- Click for more information.
Reason denied: Originally Subaru denied claim and voided warranty stating that installation of stiffer springs caused the weld to break.
Update 2011.07.21; SOA called, they're fixing under waranty, *but*... <- Click for more information.
Summary: I installed springs on my car (320lb rates, front & rear) on 2010.09.18. I have proof of invoice and tracking information via FedEx that shows I didn't have these springs in my possession until 2011.09.16. According to the dealer's service records, I first reported this problem to them on 2010.09.08. This means that it had already been occurring and I called them to set up an appointment for them to look at it. Those notes don't go into the system until the dealer takes possession of the car, at least for my dealer.
I went to the dealer today and had them print my service records. There is a 'customer complaint' on there dated 2010.09.08 that states the following;
On 2010.10.08 I brought it in because the brakes were squealing, at which time the service manager noticed the hatch squeak. I told him how I've already brought it in for that and they claim they fixed it by re-greasing the latch. He said to have it looked at again at the next service.Complaint: Customer states that the hatch back or something will creak in the rear when driving over a rough road please check and advise...
Cause: Tech traced and found there was a rattle coming from the latch on the rear hatch back door.
Correction: Tech greased the latch and test drove to verify proper operation.
On 2011.02.03 I brought it in for service and this is what they have noted regarding the squeak.
On 2011.02.07 I brought it in for the squeak again, and here are the notes.Complaint: Customer states that the rear hatch is squeaking please check and advise...
Cause: Tech test drove the vehicle and found the rear mat rubbing on the cargo cover and tech also found the latch in need of lubrication.
Correction: Tech completed the lubrication on the rear hatch latch and also moved the rear cargo mat from the cargo shade and test drove to verify no squeaking from the rear at this time.
On 2011.05.13 I brought it in for maintenance and the following was noted regarding the squeak.Complaint: Customer states that there is a squeaking noise coming fromt he rear hatch when driving over bumps please check and advise...
Cause: Tech test drove the vehicle and was not able to duplicate the customer's concern at this time.
Correction: No repairs made at this time.
I brought it back on 2011.05.18 and here are the notes.Complaint: Customer states there is a metal on metal noise coming from the right rear please check and advise.
Cause: Tech found the noise coming from the drivers rear quarter panel area more time is needed to complete diag.
Correction: Customer is advised and will return at a later date.
I did go back again near the end of may, so I'll need to go back and get that service record for the details... but in short the rep didn't even come look at the vehicle, he just told the service manager to deny the claim and void the warranty stating that my stiffened springs caused the issue, which is clearly not the case.Complaint: Customer states there is a squeak coming from the rear top of the vehicle when going over bumps advise...
Cause: Tech found the creek coming from the rear roof supports. Possible weld broken.
Correction: Subaru has been contacted and factory engineer will come out to inspect vehicle at customer convenience. Customer will be contacted when this is possible.
I just gathered the documents I think I'll need, and I'm stopping by the dealer tomorrow to talk to the service manager. I'll try to keep this updated.