2015 YUKON NOISE IN CABIN

John Dell · January 12, 2016

If this is true then why are some people complaining their wife and kids also suffer?

FogDucker · January 12, 2016

If this is true then why are some people complaining their wife and kids also suffer?

It's possible that I've got a mild case or its not in my children's audible range.

There has to be a way to measure the noise and/or pressure.

boazEarl8 · January 12, 2016

If this is true then why are some people complaining their wife and kids also suffer?

Each vehicle is different

I didn't mean to imply in ALL vehicles it is not evident in other seats, but I believe in Fog's case, it was almost non existent in some of the rear seats

The takeaway should be whoever needs to gauge the issue should be in the driver's seat

As for your order, I would go test drive it but not be afraid to walk away

Your chances of finding one will be much higher if you're willing to take one off a dealer's lot since that means you have a much larger universe of test drives

John Dell · January 12, 2016

As much as it hurts to walk away, I ordered it my way and looked forward to it for 8 weeks I think that is what I will do. My hearing is not great, [to much rock and roll] so I may here nothing then a family member sits in the passenger seat or back and goes crazy. I don't gamble or take unnecessary risks and I believe this is one. So frustrated.

yukontruckman · January 12, 2016

Actually, that is exactly what the problem looks like to me. The roof wants to pop up and the glue simply cannot hold it down, at least not for very long.

I am perfectly Ok with keeping an open mind. I really do like everything else about the truck. I just need this issue fixed.

Frank

I tend to agree. I think the following is plausible:

A: The roof is still the main problem.

B: The roof TSB does not successfully repair the problem (Most here report no improvement after the roof TSB)

C: Something your dealer did got the roof to bond (at least temporarily) since your buffeting disappeared for some time.

It could be a larger design issue with the roof sheet metal being too thin and flimsy or perhaps even the spacing of the roof bows. It may be extremely difficult to effectively brace the roof as designed.

I don't think anyone can dismiss the roof at this point solely because the "fix" doesn't work.

Edited January 12, 2016 by yukontruckman

The Zip · January 12, 2016

...the roof sheet metal being too thin and flimsy or perhaps even the spacing of the roof bows. It may be extremely difficult to effectively brace the roof as designed.

Someone on the thread made a video where he tested the bounce on the roof behind the passenger driver side door, I conducted this test and my roof did not bounce. The sheet metal was consistent throughout the entire roof, hood, front quarter panels, doors, and the tailgate. The only place on the truck that looked like the video was the rear lower quarter panels.

yukontruckman · January 12, 2016

Someone on the thread made a video where he tested the bounce on the roof behind the passenger driver side door, I conducted this test and my roof did not bounce. The sheet metal was consistent throughout the entire roof, hood, front quarter panels, doors, and the tailgate. The only place on the truck that looked like the video was the rear lower quarter panels.

Zip does your roof flex like this when you press on it?

https://drive.google.com/file/d/0B1UQB0HJVe3XcHR2TF9vd090VDg/view?pref=2&pli=1

Mine does and so does the 2016 rental I am currently in.

Elripster · January 12, 2016

I think it is also important to ensure a fixed roof is still fixed. You might do something as simple as shut the door and pop the roof off of its bows.

Frank

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John Dell · January 12, 2016

Zip does your roof flex like this when you press on it?

https://drive.google.com/file/d/0B1UQB0HJVe3XcHR2TF9vd090VDg/view?pref=2&pli=1

Mine does and so does the 2016 rental I am currently in.

This video amazes me. You all said the roof was thin but wow. GM, I hope your listening, because myself along with a few others here alone are walking away from their new SUV. Since even you believe the roof plays at least some roll in these problems please redesign the roof. Make the top thicker, get rid of that cheap[and I don't mean inexpensive] glue and redesign the side structure to add at least 2 more roof bows. I can't believe you expect people to put luggage on that paper thin roof.

Has anyone added luggage to the roof to see if the buffeting gets better? Even when glued down I wonder if the space between the bows and thin metal roof still flaps in the wind, only a very small amount of flutter will make noise. You may not even see it on video.

Jbardram · January 12, 2016

Saw this line in the GM press release rolling out the new '17 Acadia this morning, and first thing I thought was ... Wonder if this is how they wound up with buffeting roofs on the SUVS ??

"The body structure incorporates press-hardened, high strength steels, which allowed thinner components in some areas offering comparable or better crash performance than conventional materials. They also help reduce the base curb weight by 700 pounds compared to the current model"

Wrench589 · January 12, 2016

Saw this line in the GM press release rolling out the new '17 Acadia this morning, and first thing I thought was ... Wonder if this is how they wound up with buffeting roofs on the SUVS ??

"The body structure incorporates press-hardened, high strength steels, which allowed thinner components in some areas offering comparable or better crash performance than conventional materials. They also help reduce the base curb weight by 700 pounds compared to the current model"

Absolutely, the use of high strength steel is likely a big part of this. It allows less to be used, which saves weigh. But, even though the tensile strength in much high, the modulus of elasticity remains about the same. So, a lightweight part will end of thinner, and hence more flexible, even though it won't break.

And here comes the double whammy.... With less mass, it's response to vibration will get a double change. Less mass means higher natural frequency as well as less energy absorbed.

Final result is a complete change in the vibration characteristics. No surprise there is an issue, if they didn't do their design and testing homework right.

Another way to but it... Thinner sheet steel, means it more "tinny"!

Elripster · January 12, 2016

With the roof the thinner material means a lower natural frequency which can and clearly does cross paths with the disturbing frequencies. A thicker section will resonate at higher frequencies which is what you really want here. Essentially you want the body structure to resonate at a frequencies higher than that of the disturbances which requires more stiffness whether that be from thicker metal, more bracing, etc... Otherwise, if the disturbing frequency and natural frequency cross cross, you get constructive interference, standing waves and other unpleasantries.

One way to think of this is in terms of a spring and a mass. If you put a thinner lighter spring, the natural frequency of the spring/mass system goes down. Of course if you reduce the mass the frequency goes up but here the force is more in bending (at the edges of the roof) and the change in stiffness impacts the natural frequency more than the reduced mass of the roof and thus thicker metal wins by increasing the natural frequency.

Frank

John Dell · January 12, 2016

I see people/dealers using dynamat to dampen then also re glue the roof. Dynamat if flexible. My thought would be to roll or spray the roof on the inside after re glueing with a layer of something like Lizard Skin. That stuff used in the bed of pick up trucks. It is about 1/8" to 1/4" thick dries hard and don't move. That would sturdy the roof and make it stronger.

Zig10 · January 12, 2016

Did anyone else hear back from the NHTSA from their complaint? I got an email back today (submitted back in November) indicating that they are contacting GM with my info.

Don't know if that means anything, but at least they responded.

Elripster · January 12, 2016

My dealer used Dynamat and it did help with the booming. Even today the booming is not as bad. However, it does not address the buffeting as it does not stiffen the roof.

We did discuss bed liner but if there is any overspray the potential to ruin an interior is pretty high. Otherwise, it would likely do the trick.

Frank