2015 YUKON NOISE IN CABIN

[uaedenali]

I do feel bad how this suv is vibrating and booming,i have been reading this post since the first day and most of the complaints is the same to my car,i owned 2015 Yukon Denali manufactured in April since the first day i felt the booming and the vibration, i took the car to my dealer to fix the booming issue,they just did the service bulletin that gm sent but the problem still exists then i took it to other dealer who said that the roof fix done by the x dealer was not done properly so they opened the roof and fix it again and it minimize the booming a lot,there is a trick which i think it work with me to put the recirculation mode off that i feel it helps reducing the pressure, just try,for the vibration,a road balance were done but still vibrate,then they replaced the rear differential and vibration still exists, i noticed the car the higher you speed the lower vibration is exist i drove 100mph for about 3 hours and the car was smooth reducing the tire air pressure helps rubber to absorb the vibration,what i am going to do now is to change those oe bridgestone to another brand which i tested on 3 cars i owned and i am going to replace all garbage mag & airshocks to a normal gas shocks and i think beilstein 4600 is the best.let me try.

[cltsig]

My eyes hurt, after reading, the above, post.

[The Zip]

I read it just fine, there was good intent, back off a bit. But, driving 100 mph with that weight is not smart.

[bgsntth]

Zero drone or fitment issues with the GM\Borla cat-back on my 2016 Z71 after 3K miles. I drove off the dealer lot with it installed when I procured the truck. No vibration or buffeting on the truck either.

[uaedenali]

My eyes hurt, after reading, the above, post.

Use glass ur getting old.

[Damfino]

 

I haven't read any cases with the issue that had aftermarket exhaust. Most of these trucks are just days new off the lot with low miles.

 

But you can order the aftermarket Borla Catback exhaust when - (if) - you spec your truck. I did, so mine will come away new, from the dealer, with it. I'm just trying to get an idea if anyone else did and if it exasperated the problem or not.

 

 

Edit: Thanks bgsntth for the above reply!

Edited December 24, 2015 by Damfino

[ajs800]

 

But you can order the aftermarket Borla Catback exhaust when - (if) - you spec your truck. I did, so mine will come away new, from the dealer, with it. I'm just trying to get an idea if anyone else did and if it exasperated the problem or not.

 

gotcha...I've read just about every post regarding the buffeting and I don't recall seeing anyone with both the borla and buffeting, however, I'm sure the sample size is minute.

[Wrench589]

Mine has the stock exhaust - no Borla - and has the vibration and buffeting/pressure issue.

 

Interestingly, I has to run to the store the morning and the vehicle basically exhibiting not noticeable buffeting. The vibration was there, but possibly less - hard to compare to last time I drove it a few days ago. But for sure the buffeting was almost non existent. Just an extremely slight shudder once in a while, times with the vibration.

 

So why? Don't know. I do know that it's a bit cold here right now. The vehicle is parked in an insulated garage but the heat is turned off. Outside temp is -15C. I also noted the tire pressures are a bit down, to 30 psi, per the TPS. Could be helping? Maybe. I never did play around with tire pressure in the summer. I think the normal pressure was around 33-35 psi, which isn't that much different, but maybe with such a low profile tire, make a big difference?? (22")

[Elripster]

Lower tire pressure will definitely reduce the sharper road inputs to the chassis. Cold weather though will also essentially stiffen the shocks due to the oil getting thicker. It sounds like the tires being lower helped more than the shocks being stiffer hurt.

 

Frank

[Wrench589]

Frank, yea I would expect colder to be worse. Colder oil in the shocks. Colder body mount rubber. Colder suspension rubber bushings. Colder tire rubber.

 

I will admit it was Avery short trip. On,y about 5 miles round trip. But, usual the worst buffeting is the first 5 miles, so it worth noting.

 

A word about tire rubber. I happened to have a meeting with a professor at the local university engineering department a few month ago. His specialty is polymers. We were meeting on something related to my work but in the conversation he made a comment about tires, since of course all modern tires are synthetic rubber. I took the opportunity to derail the meeting for 5 minutes to talk about tires and turns out one of his grad students now works for Goodyear at their research centre! Anyway, bottom like is the tire industry has changed the way they make synthetic tire rubber over the last 5-10 yrs. it has to do with the way the cross linking is done on a molecular level. Now, the new rubber tends to be stiffer but, is affected less by temp changes. So hard to say what "stiffer" means - at what temp? I suspect the new polymer also wears better? Anyway, was interesting if nothing else. And by the way, the new process is cheaper and faster!!

[Wrench589]

Has anyone wondered how much the Road Force number really are? To put it in perspective, I did a calculation to take the Road Force force and compare to an equivalent amount of mass unbalance at 110 kph, on my 22" wheels and tires. Here's what I got:

 

35lb RF = 1.6 oz (original GM spec for trucks with LT tires)

24lb RF = 1.12 oz (original GM spec for trucks with P metric)

18lb Rf = 0.84 oz (original GM spec for cars)

15lb RF= 0.7 oz (revised GM spec for trucks and SUVs with vibration and drone/pressure issues)

 

And, this is total mass unbalance. Often, this is split between inside and outside bead of the rim. So, for arguments sake, think about half and half.... So that looks like a 0.35 oz weight on the inside and another on the outside of the wheel. That's not a lot. Noticeable, yes. But not a huge amount, for sure.

 

Puts it in perspective, I guess. For what it's worth.

[Elripster]

Well after further inspecting the previously repaired roof I noticed the bow behind the sunroof is detached. As a result the roof is starting to lift there. That has me concerned about sealing water as the miles and years wear on. As a result I have initiated a repurchase.

 

It almost looks like the the roof structure is too narrow by just a little bit causing the roof to bow upwards and pull itself off of the bows.

 

Frank

[Wrench589]

Well after further inspecting the previously repaired roof I noticed the bow behind the sunroof is detached. As a result the roof is starting to lift there. That has me concerned about sealing water as the miles and years wear on. As a result I have initiated a repurchase.

 

It almost looks like the the roof structure is too narrow by just a little bit causing the roof to bow upwards and pull itself off of the bows.

 

Frank

That definitely sucks. It's weird that some roofs have the problem of the roof pulling away at the sunroof and others don't. GM must really have to quality control over that part of the fabrication and assembly. Atrocious!

[boazEarl8]

I'm not sure how to understand your RF math, but I know one of my wheels needed 8oz of weight to get the values under 10lbs

[Wrench589]

The math is essentially calculating the equivalent weight/mass unbalance that produces a certain force, in lbs., at a certain speed. I used 110 kph. Basically calculated based F=ma using angular velocity to determine the centripidal acceleration.

 

Have to remember that the weight you see on the wheels is not there to correct for Road Force Variation, even when it's been on a Hunter Road Force machine. The Hunter machine uses "Force Matching" to position the tires on the wheels in the most optimal combination so any runout of the wheels can be set opposite to annoys RFV in the tire and cancel each other out. After that is done, then the weight balancing is done, essentially in the traditional process. The Hunter GSP 9700 does not add weight to correct for RFV.

 

There are limitations to how much Force Matching can be done. For example, if the wheels are perfect, then you are stuck with the tires as they are. There is no correction. To do the best job possible, supposed to start with bare wheels and measure the runouts. Then mount the tires and take he RFV readings. Then the computer will calculate the optimal arrangement of which tire on which wheel and in what orientation. Many many hours of work.

 

According to Hunter, recently they are finding a lot of trouble with getting accurate and repeatable RFV readings because of improper bead seating. Apparently, the technology in the beads and wheel seat has changed and it's more and more tricky to get the bead to seat properly. And, can't see it from the outside. Supposed to use lots and list of lube and even over pressure to get the beads set properly, then "drive gingerly" for the first 500 miles to prevent slippage! Yes, that is what Hunter is saying. Hunt even says can deflate the tire then overinflated to attempt to correct the bead (up,to max pressure, of course). So, I wonder is some of these changing RF results on tires is this going on?

 

The other interesting thing Hunter says is that the results of the RF readings should not be used to reject a tire! That's interesting.

 

Last thing...several GM Bulletins, as well as Hunetr, clearly say that the tires must be driven for at least 15 miles just prior to doing RF balancing to remove any flat spots and warm the tire up. I wonder how many dealers do that, especially when they get a brand new replacement tire in! ( I realize a new tire won't have a flat spot, but certainly won't be "warmed" up.

Edited December 25, 2015 by Wrench589