2015 YUKON NOISE IN CABIN

FogDucker · January 21, 2016

I went to back of my car opened the hatch and started looking at various places in detail. I noticed that the hinge on the right side did not seem symmetric to the ones on the left in terms of how they were joined. The positions of the bolts were slightly different. Upon a more careful inspection I found that the hatch was leaning down from the right side slightly (not easy to notice though). I could also point out the impact point of the hatch to the body on the right side (at the bottom of the hatch), some paint has also been damaged there.

Any chance you could annotate and upload a picture? Are you referring to the hinge on the body of the truck, at the very top?

The hatch theory is relatively new. Booty did report it months ago, but he was mostly ignored. It might have been because of his thick Carolina accent. ;) [Loved the "Hee Haw" reference Booty!]

I don't recall anyone in this thread having their hatch inspected by their dealerships/technicians. Booty observed that buffeting SUVs had loose hatches and found a quiet one that had a tightly closing hatch. I was able to manipulate the buffeting by stuffing foam in various places and adjusting the stops, but not consistently. Maybe it's because I was stuffing foam symmetrically.

boazEarl8 · January 21, 2016

Any chance you could annotate and upload a picture? Are you referring to the hinge on the body of the truck, at the very top?

The hatch theory is relatively new. Booty did report it months ago, but he was mostly ignored. It might have been because of his thick Carolina accent. ;) [Loved the "Hee Haw" reference Booty!]

I don't recall anyone in this thread having their hatch inspected by their dealerships/technicians. Booty observed that buffeting SUVs had loose hatches and found a quiet one that had a tightly closing hatch. I was able to manipulate the buffeting by stuffing foam in various places and adjusting the stops, but not consistently. Maybe it's because I was stuffing foam symmetrically.

What happens if you drive around with the rear glass open? Open should also alleviate any drumming between the glass and seal, right?

FogDucker · January 21, 2016

What happens if you drive around with the rear glass open? Open should also alleviate any drumming between the glass and seal, right?

Oh sure, ask the Canadian to drive around with the hatch open in January. ;)

That's a good question. It might alleviate it, unless the root cause is the hatch bouncing around on the frame/opening of the rear of the vehicle in ways that it shouldn't. Remember how pounding on the inside [see white oval in attached pic] of the hatch produces "the boom"? Could this be it, because of a misaligned or mis-installed hatch? Flashback to a post from last June.

Edited January 21, 2016 by FogDucker

FogDucker · January 22, 2016

Show of hands.....

Who has crossbars on the roof rack, who doesn't, and who is experiencing the "buffeting" and who isn't.

Me - no crossbars, yes buffeting.

Nearly a year has past since Wrench asked this, but could we revisit this? Could those with crossbars please report in? Do crossbars, or things attached to them, influence buffeting? Does anyone here use cargo boxes? Is there anyone with crossbars that does not experience buffeting?

My updates: The raised 3rd row seat is one thing that changed with the new K2XX SUVs. I folded a towel lengthwise [4 layers] and placed it in the hatch as shown in the attached picture. The hatch closed snugly but there was no difference in buffeting. Interestingly, I was able to pull the towel out from the inside of the hatch. So, the hatch and the angled shelf are not making contact. They're not even that close!

I also drove down a snow covered street with with the rear glass open and then again with the hatch open. No change to the booming. I was not willing or able to drive it up to the 40mph buffeting sweet spot to see if it changed with either open.

My Yukon has another date with a field engineer on Tuesday and it'll be in the shop for at least 2 days, I'm told. He'll be focusing on the hatch, exhaust [?] and maybe crossbars. [i don't have crossbars, but will need them if I keep the Yukon.]

~2 months until my annual 1,500 mile drive to warm Florida with the brood. I'd like it to be a buffeting free drive!

Wrench589 · January 22, 2016

Marc, that's very interesting that when you drove it with the glass up and the hatch up, you still heard the booms. Really make me believe the source is not the rear hatch, but some other large surface - roof, rear quarter panels, floor, firewall, etc.

I read a appear some time ago that said the firewall often is the source. I thought that was interesting. Would have never thought.

I wish I had more time to test and experiment. I have over a thou sound dollars worth of microphone equipment I bought to do some detailed audio testing in an attempt to positively identify the frequency, the amplitude, and then try to do some intensity testing to zero in on the location of the source, although I think the latter will be next to impossible with such a low frequency sound.

Getting back to one of my ongoing observations - Marc, have you sat in the second row and swung the rear door open and closed through the detents? I definitely hear the boom when I do that.

Booty · January 22, 2016

Any chance you could annotate and upload a picture? Are you referring to the hinge on the body of the truck, at the very top?

The hatch theory is relatively new. Booty did report it months ago, but he was mostly ignored. It might have been because of his thick Carolina accent. ;) [Loved the "Hee Haw" reference Booty!]

I don't recall anyone in this thread having their hatch inspected by their dealerships/technicians. Booty observed that buffeting SUVs had loose hatches and found a quiet one that had a tightly closing hatch. I was able to manipulate the buffeting by stuffing foam in various places and adjusting the stops, but not consistently. Maybe it's because I was stuffing foam symmetrically.

Fog, GM should move the assembly plant to North Carolina ! These good ole Nascar boys can build and fix damn near anything. The first thing they would do is take the robot out of the assembly line and teach it to cook ribs . If my car had a problem I would run it over to Dale's house and let him take it for a ride and it would be fixed when he drove back up the road to the house. Carolina boys and girls are the best when it comes to cars and trucks. They are also the nicest people to live around. Regards, Booty

boazEarl8 · January 22, 2016

I have to go revisit, but I could swear that I felt very minimal booming on my test drive (with cross bars attached) and seemed worse after I had them removed prior to delivery since I assumed more turbulent air (driven by cross bars) would make the issue worse

Thank you for driving with the rear open, mine is at the dealer for an unrelated issue

Edited January 22, 2016 by boazEarl8

FogDucker · January 22, 2016

Marc, that's very interesting that when you drove it with the glass up and the hatch up, you still heard the booms. Really make me believe the source is not the rear hatch, but some other large surface - roof, rear quarter panels, floor, firewall, etc.

I read a appear some time ago that said the firewall often is the source. I thought that was interesting. Would have never thought.

I wish I had more time to test and experiment. I have over a thou sound dollars worth of microphone equipment I bought to do some detailed audio testing in an attempt to positively identify the frequency, the amplitude, and then try to do some intensity testing to zero in on the location of the source, although I think the latter will be next to impossible with such a low frequency sound.

Getting back to one of my ongoing observations - Marc, have you sat in the second row and swung the rear door open and closed through the detents? I definitely hear the boom when I do that.

Yes, I remember you suggesting this many months ago and I tried it. It sounds like a variation of the boom. Mechanical resonance? I missed that day of school!

@boazEarl8: The crossbars may disrupt the air flow in a good way! Hopefully we hear back from more people about this. Else, I should have a pair installed next week.

Someone said this before [it may have been you Wrench], our trucks are big, elaborate tuning forks and there are many triggers that can get it to sing including bumps in the road, doors swinging through detents and maybe even fluttering body panels. I can live with the 'bump boom' and only wish they isolate the 40mph and 70mph triggers which we have been referring to as "buffeting". Maybe there is a way of damping this very specific resonance. This is all outside my area of expertise and interest.

I just want to enjoy driving my Yukon Denali!

Wrench589 · January 23, 2016

I just had a thought that I figured I would share. I don't know a lot about the electronic steering in these vehicles but I recall some discussion about it and "smooth road shake". From what I recall, the electronic steering does have some kind of logic to try to dampen or cancel any smooth road shake.

What I don't recall anybody reporting from their dealer is any measurements from the Hunter Road force balancer on the lateral measurement it can take. I'm wondering if for some reason there is excessive or significant lateral forces that are causing the electronic steering to get too "involved".

Anyone have any comments from their dealer about the lateral measurements on the Hunter?

sas06 · January 23, 2016

FogDucker!

Yes I do mean the hinges on top of hatch (the two hinges on left and right). They are not symmetrically attached. Photos won't reveal much due to minute nature of differences in the two hinges.

In response to your towel test I think that booming is due to the roof sheet instead of the hatch, and hatch is only responsible for buffeting. Imagine being in an airtight container and then any flexing in the roof sheet will hurt the ears and create booms. The roof sheet is very flimsy. On top of second row seats it is so thin that you can press it down with one finger without much force. When I opened the rear hatch door stoppers the booming subsided probably because the cabin is not as airtight as before. But that is not the solution as opening the door stoppers increases the road noise. If you open them just enough to make the hatch a bit tighter you can affect buffeting. Buffeting may subside or go away at certain speeds or re-appear at certain other speeds.

As you are telling that buffeting in your case appears at 40 - 50, makes me think that your hatch door is more loose than mine as in my case the buffeting only happens at 110+. Tomorrow I am going back to the dealer and putting the car in for checking the hatch.

I also might suspect that the rear axil might be producing some vertical vibrations, which in turn may excite the hatch a bit too much.

boazEarl8 · January 23, 2016

I also drove down a snow covered street with with the rear glass open and then again with the hatch open. No change to the booming. I was not willing or able to drive it up to the 40mph buffeting sweet spot to see if it changed with either open.

Doesn't this show us why there's no fix almost 2 years later? Shouldn't opening the tailgate eliminate any issues since the cabin pressure is now equal to the outside? Or, at the very least, the issues should be greatly reduced?

Wrench589 · January 24, 2016

Doesn't this show us why there's no fix almost 2 years later? Shouldn't opening the tailgate eliminate any issues since the cabin pressure is now equal to the outside? Or, at the very least, the issues should be greatly reduced?

It does seem logical that it shows the boom is not caused by the rear lift gate. Unless, the sound isn't emanating off the hatch itself, but rather exciting the roof via the hinges?? Then, open or closed, could still contribute to the boom?

Only way to test that is completely remove the rear lift gate altogether. Which is, of course, a pretty big job and drastic step for us DIY'ers!

FogDucker · January 24, 2016

It does seem logical that it shows the boom is not caused by the rear lift gate. Unless, the sound isn't emanating off the hatch itself, but rather exciting the roof via the hinges?? Then, open or closed, could still contribute to the boom?

Only way to test that is completely remove the rear lift gate altogether. Which is, of course, a pretty big job and drastic step for us DIY'ers!

Assuming, of course, that "the boom" and the "buffeting" are the same. I'm not sure that they are.

Wrench589 · January 24, 2016

Assuming, of course, that "the boom" and the "buffeting" are the same. I'm not sure that they are.

Fair enough. I'm still on the fence on this. Sometimes when I'm driving it, I think it the same sound, sometimes I think not. Haven't got any empirical data yet to support either.