2015 YUKON NOISE IN CABIN

FogDucker · January 1, 2016

The buffeting and booming has improved with foam placed at the top of the hatch. See the orange arrows in the picture [the left piece shifted before I took it]. I don't believe the stuff at the bottom makes a difference, but I'm trying to change only one thing at a time.

Can anyone else reproduce?

yahtzee · January 1, 2016

It's pretty cool to see all these publications and news authorities reporting these issues for the 2015 Tahoes, Suburbans, Yukons, Denalis and Escalades. But, they are missing the reports on the 2016 model years that also have some of the same exact issues. Most are only reporting the headliner fixes and not the PIT5429 bulletin that first addresses some of the other issues such as the harsh ride, noises, vibrations.

Highly recommend sending email/commenting on article about any other details you feel are missing. The more we send them the more likely they are to respond (as already evident).

Jigsaw786 · January 2, 2016

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Hello guys, after reading all these comments and posts about the 2015 Yukon's, XL, suburbans, etc. I now know that I'm not going nuts or crazy. Now I can actually see that so many other customers are having the same exact problem as me.

During my first visit to the dealership, I took it it for a clanking noise coming from the transmission. The dealer kept the car for about a day and when I picked up the car, they told me that the car had an 8 speed transmission which supposedly makes the system act funky. They did an update to the software of the transmission which was supposed to fix the problem. I took the car home and the clanking noise was still there; however I did notice it wasn't happening as often as it was before. When we took a drive to Vegas, we noticed a vibrating or "droning" sound which was irritating to our ears. When I came back to San Diego, I took it to the dealership and told them about the problems I was having (droning noise and clanking sound). They kept the car for another two days, eventually telling me that they couldn't find the problems I was having so they told me to take a ride with a technician and try to duplicate the problem. While we were trying to explain to him what we were hearing, he was denying the problems and saying he ho couldn't hear anything. During this process, I had already opened a case with GM and told them that the dealership cannot solve the problem. After they refused to deal with my car, the GM representative told me to try taking it to another dealership. When I took it to another dealership, I had to take a ride with another technician and I was told that they actually don't have a solution to the problem so they didn't want to do anything that would worsen the problem. During the process, the dealership they didn't check me in or anything as they were supposed to. At this point, I contacted GM and told them that the dealership told me that there is no fix for these issues so they put me into a buyback process. When I spoke to a buyback representative, she told me that she doesn't have enough evidence in order to further the buyback process as the dealerships did not put in writing what they had told me verbally (that these problems don't have a fix so they won't do anything about it). Then I took it back to the same dealer that I had bought the car from, and explained to them about all the problems again,. They kept the car for a month, giving me a 5 passenger loaner vehicle. After a month, they told me that they made some adjustments to the roof and taillights which they didn't put in writing. They also told me that these sounds that I am experiencing with a $60k+ vehicle are perfectly normal. I am now very tired of trying to deal with them and hoping they will just buy back this car from us. We will be taking it back to the dealer soon and will update.

Snoringbear · January 2, 2016

Good news. Saw on Fox and Friends just a few minutes ago a news spot about this problem. Stated that GM is aware of the problem but a solution is complex (paraphrasing). Anyway, appears that The General has at least acknowledged that there is indeed a problem. Guess that's progress.....

Zig10 · January 2, 2016

The buffeting and booming has improved with foam placed at the top of the hatch. See the orange arrows in the picture [the left piece shifted before I took it]. I don't believe the stuff at the bottom makes a difference, but I'm trying to change only one thing at a time.

Can anyone else reproduce?

The orange arrows at the top would make more sense based on what others have written regarding the glass pulsating. With the common hinge for both the gate and glass, maybe that is tightening up the whole assembly when you put pressure there. Have you tried putting down self-adhesive weather stripping on the glass itself where it meets the rubber gasket? I bought a roll from the hardware store to test it, but I never got my car back to try it out.

FogDucker · January 2, 2016

The orange arrows at the top would make more sense based on what others have written regarding the glass pulsating. With the common hinge for both the gate and glass, maybe that is tightening up the whole assembly when you put pressure there. Have you tried putting down self-adhesive weather stripping on the glass itself where it meets the rubber gasket? I bought a roll from the hardware store to test it, but I never got my car back to try it out.

Yes, I stuffed the glass portion with foam, making it very snug to close. Unfortunately, I did that experiment with the main hatch and don't know which helped/hurt.

For now, I'm just focusing on the hatch, specifically the top.

Be sure to listen for the slow speed bump boom and the 40 mph/60 mph buffeting!

uaedenali · January 2, 2016

Today I went to install kooks 1 7/8 long tube headers but unfortunately didn't fit,the headers was hitting the steering shaft.

Wrench589 · January 3, 2016

I did some rough calculations of the Helmholz frequency and it's not close to the frequency that I have measured the buffeting to be at. I measured a sound pressure spike between 25 and 30 hz, while the Helmholz frequency for the size of the Yukon XL cabin size is over 40 hz as I recall (been about a year since I did it!). And FYI, the non-XL would be even higher frequency, being shorter.

A Helmholz quarter wave resonance would be completely independent from any flexing of the roof skin or moving of the hatch. A quarter wave resonance is a standing wave inside a tube and does not need the tube walls to be flexing to have the standing wave. To help visualize, think about blowing across a glass bottle top. The sound you hear is the standing wave of the air inside the bottle, but the glass isn't "flexing" much, is it?

Not to say that a quarter wave resonance couldn't excite a flimsy surface of the container it's inside of. But that would be a result of the standing wave, not the cause of the standing wave.

That said, the buffeting is definitely a result of something flexing/vibrating. And that something is likely a very large surface.... Roof, floor, firewall, rear lift gate, rear quarter panels. Something like that.

As for the roof skin being attached to the bows or not.... From what I saw of the cross bows, they are very flimsy looking. And, the spacing between them is quite large. So, I would suspect that if the roof is the issue, then attached or not there will be a problem. Maybe the severity will vary, but if don't think the bows are sufficient to do the needed job.

Wrench589 · January 3, 2016

Lately, my Yukon XL is behaving slightly different. Not as bad as it used to be. The low speed drone over rough surfaces is the same - BAD! But, the buffeting seems to come and go. I almost have convinced myself I can detect it coming and going with varying the torque load in the driveline (driveshaft). Almost seems like it goes away when the load is neutral (ie coasting). But, slipping the transmission into neutral does not eliminate the buffeting, so that would kill that theory. Still, I do hear it coming and going.

Ultimately, I think any vibrations felt by the body are generating the buffeting. Seems like those vibration sources can be tire/wheel, roiled road, driveshaft balance, u-joints, ring and pinion, etc. it will be impossible to eliminate all these. The solution is to de-tune the body/frame assembly. That includes even if it's the rear hatch, and it sound like FogDucker might be on to something.

Question, FogDucker.... Did you do any adjustments to the stops at the bottom of the hatch? Did you notice there is a second set of stops above the lower ones, and I'm wondering how critical it is that the two are adjusted correctly relative to each other and the body seal itself. One way to test the amount of seal is to put a strip of paper between it and the hatch, close the hatch, and try to pull it out. And, test all the way around. Haven't had a chance to check mine but I will one of these days!

FogDucker · January 3, 2016

Question, FogDucker.... Did you do any adjustments to the stops at the bottom of the hatch? Did you notice there is a second set of stops above the lower ones, and I'm wondering how critical it is that the two are adjusted correctly relative to each other and the body seal itself. One way to test the amount of seal is to put a strip of paper between it and the hatch, close the hatch, and try to pull it out. And, test all the way around. Haven't had a chance to check mine but I will one of these days!

The only adjustable stops I can see are about half way down the hatch. I've gotten better results with it a few turns from flat. Too far extended or too "closed" and the boom / buffeting was worse. I've read the paper trick to measure for a the right seal too - simple but effective! I haven't personally tried that yet. The bump stops at the bottom of the hatch seem to be only that - rubber bump stops.

I've done some more foam insulation experimentation - tape some on, drive. Move it around and drive some more. The attached picture is the best I've gotten it. The low speed bump boom is significantly better. 40mph / 70mph buffeting is still there, but has improved. Styrofoam along the bottom, especially in the corners have made the biggest impact for the low speed boom. The hatch *just* closes on it's own - I sometimes have to give it a bit of a push to keep it from re-opening. Next steps are to focus on the area above the bottom hatch where the 3rd row seats fold - that *is* new for 2015/2016 and it's possible that the hatch is bouncing off that.

The styrofoam I'm using is the soft flexible kind, about 3/8" thick. The fluffy stuff seen in the cargo area wasn't as useful as it compressed too much.

It would be awesome to see more owners conduct this same experiment to see if they can *influence* [not necessarily fix] the boom/buffeting via the hatch.

Booty · January 3, 2016

Same here. 2 new tires, many balances and a complete rear axle. It did make for a smoother ride, but had no affect on the buffeting. I believe that the vibrations and the buffeting are two distinctly different issues.

The buffeting may all be related to Helmholtz resonance. There are many interesting articles about this online, such as this one or this one. The examples speak mostly about when one or more windows are down and the car drives at speed. I think we're experiencing a variant of this with our windows up. Bumps and/or swirling air [different pressures, "vortex shedding"...] may be causing the hatch [or rear glass] to move - bouncing in/out and causing the buffeting. We are inside a really big speaker and the hatch/glass is the woofer. The Tesla folk had a nearly identical experience, solved by correctly fitting the rear hatch stops. So did some Porsche models - all had hatches. Who knows, maybe the slow speed "boom" might simply be the hatch shifting around in ways that it shouldn't.

I've been experimenting with this over the last couple of days and have been able to manipulate the buffeting via the rear hatch and/or glass. I've adjusted the bumper stops and placed styrofoam pieces in various places, both on the hatch and the rear window seal. Sandwich it in top, bottom, sides... I've got the buffeting to get worse and better by limiting the amount of inward travel. Where exactly, I'm unsure.

Air/pressure/Helmholtz also fits nicely with what we've observed - buffeting can affect any of our K2XX SUVs irrespective of wheelbase size, engine size, transmission type and options. All of our SUVs do share the same seals [?] and hatches. The pickup trucks do not have this problem.

Happy New Years to all.

Dear Fog, I spoke about this on Page 93 #1394, 94, #1400 and 95 #1419 and was totally ignored. QUOTE " Closed minded scientists never launched a rocket" I am glad YOU now understand. I think you are the right track to solve this problem. My hat is "OFF " to you. Booty Good luck. Happy New Year to you.

FogDucker · January 3, 2016

Dear Fog, I spoke about this on Page 93 #1394, 94, #1400 and 95 #1419 and was totally ignored. QUOTE " Closed minded scientists never launched a rocket" I am glad YOU now understand. I think you are the right track to solve this problem. My hat is "OFF " to you. Booty Good luck. Happy New Year to you.

@Booty: I remember your posts. In fact, I remember going outside to push on the tailgate glass just as you mentioned, but could find no flex. Can you tell us how you are able to determine if the seal isn't proper? Is it just a matter of inspecting the rubber seal when the glass is lifted? I just checked mine again just now with a flashlight but can't see anything wrong from the outside. The gap looks consistent and pushing on the glass allows for minimal flex. There doesn't seem to be any stop adjustments as there is on the tailgate.

Wrench589 · January 4, 2016

I definitely notice that the bottom corners of the rear lift gate do flex in a fair bit when I push on them. I was thinking that the main bump stops, which are just slightly below mid-height, are holding the lift gate fixed from the top hinge to them, but the remaining lower portion is somewhat un-supported as the small bumps stops on the bottom seem less substantial and not being adjustable, no way to get them tight. Of course, making them too tight would simply push the gate off the middle stops, and then the middle of the gate would be unsupported! Kind of reminds me of the difference between a 3 legged chair and a 4 legged chair!

I tell you what...it would not surprise me in the least if the rear lift gate was the cuplrit. How to prove it absolutely may be a bit tricky, though.....

I guess one thing I could do is remove the inner panel from the lift gate and expose the inside. Then, I could put the accelerometer from my vibration analyzer on the inner skin of the gate and see what kind of vibration levels there are when driving. I did not want to put the accelerometer on the outside mainly be cause the magnetic mount will definitely scratch the paint. Not too keen on doing that!

Here's a question for you all....does everyone having this issue have the power lift gate option? One thing I notice about the power lift gate option is that the latch does seem all that positive. Seems more like a motorized device that pulls the gate in. But I'm not sure how strong it is.

Edited January 4, 2016 by Wrench589

Elripster · January 4, 2016

Ours seems to close fine. Seeing as how our truck's issues completely disappeared when the roof bows were attached I would say that while a lift gate could cause issues there is no way it is "the culprit", at least not across the board. Maybe it can exacerbate the roof issue if you have an issue with the roof.

Frank

Romeo Serban · January 4, 2016

4 knucks - I am guessing these are some intelligent GM folks looking at your 70k truck the dealer has been experimenting with for ten days. But if the drivetran is the issue, why don't these guys apply some smarts and look at the Tahoe. I say this not because the Tahoe is better, but there is not a big difference in Yukon/Tahoe drivetrains. Those two vehicles have similar torque and is about even in transmitting their respective horsepower to the wheels. Other than some interior features and exterior lighting and grill, these trucks are interchangeable.

My point being, tell these guys to close the door and look at some Tahoe's to see what's working. This may help them to find out what's not working in your Yukon. I don't experience this problem at any speed in the '15 Tahoe.

Hi there

I own a 2015 Tahoe. Same story. It also has a roof leak and I have no sunroof. When you roll the rear windows down it makes an umberable noise. Don't know how to describe it.