Vibration noise from ... the roof?!?

[AHels]

So I'm on my way home this afternoon and I get stuck behind what can only be described as a convoy of road-trains..

Anyways, we have a stretch of road where visibility is easily a mile, so I hit the accelerator and start overtaking..

Everything's fine until I hit about 95mph and I hear this ... vibration noise from the roof.

Seems to come from right above the steering wheel, so I pull over at the next restarea to check it out. Figuring it'd be the antenna vibrating in the wind, hitting the roof. I have a look and the aerial is pointing right up like always.

Check the marker lights (which seem like they're a bit loose, but I seem to remember they've always looked/felt that way). Check the cross bars are fastened properly (moved them last week as I transported some wood), seem fine. What I do notice is the actual cross bar mounts (ie. the tracks) seems loose at the front. I don't really think this would cause the noise I heard, but well...

Checked the TSBs but all I found was Reports are being received on customer complaints of roof rack rattles. The cause of this condition is that the cross bar mounting screws on the passenger side are loose. They are intentionally left loose upon shipping to allow for any necessary adjustment upon installation of the roof rack assembly at the dealership. Be sure to tighten these screws to 4.5 Nm or 40 in. lbs. upon installation. Refer to step #3 and figure #6 of the installation instructions. which doesn't seem to be the cause either.

So, any ideas on this? Am I missing something obvious? It wasn't even that windy - and the noise reproduced easily when hitting those speeds again.

Should be noted that I regularly push the limit of what the H2 is capable of on that stretch of road and never heard it before.

[f5fstop]

Subject: Service VME - OnStar Antenna Mast Rattle - keywords cellular noise roof #PIT4010 - (05/16/2006)



Models: 2006 Hummer H2 SUT and SUV




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

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

SERVICE VME
If a customer complains of a rattle above the driver?s head at highway speeds, one possible cause can be the OnStar antenna mast. This can be confirmed by removing just the mast portion of the antenna assembly to see if the noise disappears. To correct this condition, bend the mast to slightly impart a kink in the metal core wire. If this does not correct the condition, replace the antenna mast.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

[SUT NEIL]

Sunroof wind deflector vibration usually occurring at 65 + mph is a common problem and is most likely what you experienced. I think the fix is covered under the hummer warranty. I know there are other posts on this forumn concerning this issue.

[Dug]

<<It wasn't even that windy>>??

Hehe , you were going 95mph.. Stick your head out the window and i think you'll notice it was a little windy. ;)

[AHels]

f5fstop: Thanks very much. Will try that tomorrow. Are these TSBs available for free on the internet anywhere? I'm relying on the GM SI DVD and AllData, none of which are _that_ up2date.

SUT NEIL: No sunroof on this one I'm afraid, otherwise that'd have been my first stop :)

Dug: Mmm, true dat :D What I mean is I can normally hear/feel the wind bashing the car around when it really is windy. I couldn't this time.

[f5fstop]

That type of bulletin is not, since it is technically a preliminary information type and not a printed bulletin.

[GeorgeSSSS]

Just saw your post.

My suggestion is to pull back the roof sunshade (keep the clear plastic sunroof closed), go 95 mph, and have someone look out the sunroof. As goofy as it sounds, it's easy and sometimes works. I had a vibration at 80 mph. I had one of my sons look up through the clear plastic sunroof while I drove and it turned out the noise was one of the power cables for the lights on my GOBI roof rack. I use a couple of cable ties to solve the problem. Cost: Zero (I already had the ties in my garage).

Good luck,

George SSSS

[MONSTERMATT]

could it be the seal on the windshield? i have the same issue and i was told it may mean the window needs to re-sealed , suposedly it is a "common" problem and covered under warranty at the "stealership"