Yukon XL/Suburban booming noise

[mcglover]

I have a 2000 Yukon XL SLT with load leveling suspension. It has about 50K miles on it and is in near perfect condition. It has the factory Firestone Wilderness LE tires on it.

 

I bought the car from a dealer in Bellevue, Washington. The area around the dealership is all smooth, new blacktop. The car ran great, and I loved it. I then drove it home for my wife to see. We live in an older part of Seattle with concrete roads, meaning expansion joints. My wife immediately said "What is that noise?", referring to a loud booming sound in the cabin, noticeable mostly in the front seats.

 

Over the ten months since I bought the car, this noise has become very annoying, if not painful at times. Whenever the car moves at speeds between

 

1 mph and 35mph, the noise is very bad. At 5 mph, it can be very bad. Above 35, it seems to taper off, or become masked by other road noise. If I crank up the stereo, it helps, but then I do not always want to listen to loud rock and roll.

 

I work for a company that supplies generators to the megayacht business. We build highly developed sound enclosures for our machines. We have a lot of expensive testing equipment, including a CEL 440 hand held digital sound meter.

 

Today, we took a ride in the car and ran sound level tests in the cabin. We drove the car on normal, concrete pavement with expansion joints. I estimate that segment of road is about ten years old and in reasonably good condition. No potholes. We ran the tests at between 25 and 28 mph. We ran tests in the front, middle and rear seat positions respectively. What we found is this:

 

1. The front seat area was the worst for the noise measured.

 

2.a. 125Hz measurement at this point: 81.4 dB

 

2.b. 63Hz measurement at this point: 84.8 dB

 

2.c. 32Hz measurement at this point: 102.5 dB

 

3. The middle seat tests were about 10% numerically quieter than the front.

 

4. The rear seat tests were about 15% numerically quieter than the front.

 

I note the "numerically" quieter feature because dB are measured on a logarithmic scale, where 3dB increase gives an apparent doubling of noise.

 

Since human hearing is effective at levels above 20Hz, this is not insignificant noise. I was shocked to find out just how loud this problem is, and would like your help understanding what might be causing it and finding out if GM is doing anything about it.

 

Last summer, I drove a 2004 Yukon XL SLT with Autoride. The noise was essentially the same as my car, in my opinion.

 

I find is incredible that anyone buys these cars, or keeps them for any length of time. The problem is most noticeable in cold weather, and if you have a head cold and sinus congestion, I would not be surprised if actual damage could be done to your hearing.

 

Thank you for any help you can provide.

 

Doug McElroy

[Markeaux]

Do the results change if one or more windows are open? If the AC system is set to Recirc or not? Either of those may affect cabin pressures and sound. And aren't there cabin pressure vents in the rear D pillars?

 

Maybe try different tire pressures? Maybe that will lead to a clue of it being tire induced noise. And, it seems different types of tires may produce different cabin noises. (The oem Wilderness LE's were mushy on my 01 Tahoe, I was glad to be rid of them.)

 

Maybe leave the trans in a lower gear and retry (ie, change the rpm's), like to help rule out some rotational engine/tranny noise.

 

Just trying to give some ideas ...

[PunchT37]

Check for scalloped front tires, usually just on the inside row of Wilderness tires.

Tahoes and Subs. are famous for this. Rotate the tires and see if the noise

changes or goes away. Take the rear and move to front,and take the front and

move to rear,but cris cross them to make them rotate oppisite on road. Tires

may be shot already though.

[boomer 33]

Sounds like you are driving with the back windows down, or with the sunroof open all the way. Both of those cause a huge booming sound do to air pressure. The sunroof will blast you at any point past half open, either rear window will do the same.

[mcglover]

Check for scalloped front tires, usually just on the inside row of Wilderness tires.

Tahoes and Subs. are famous for this. Rotate the tires and see if the noise

changes or goes away. Take the rear and move to front,and take the front and

move to rear,but cris cross them to make them rotate oppisite on road. Tires

may be shot already though.

No windows open. Tried all kinds of pressure in tires. No change.

 

I will try changing the tires around, but why would this help if it happens on a brand new car as well? The new one has the same tire brand/model.

 

Thanks for the effort.

 

 

DOug

[C & A s Dad]

Doug, my 02 Yuk XL is one of the most quiet vehicles I have owned. I will say when I removed the junky wilderness LEs and put some really good tires on the truck, it changed the entire ride and sound. I put a set of B stone HL Alenzas on it and have been very happy.