Noise on Highway
 

The noise usually takes 20 minutes of driving at highway speeds to start making the noise and then it is nonstop. It doesn’t always make the noise, so the service dept can’t figure it out. The noise occurs with the radio on or off. It sounds like a crackle or pop. Thx for any help! The car only has 30,000 miles on it.

Forgot to mention...
 

The vehicle is a 2020 Yukon Denali XL. Thx.

Welcome to the forums.
This vehicle is fully under warranty I assume.
Sound more like a rattle or something may not be tightened correctly.
From the driver's area do you feel any vibrations?
Is this just an interior noise? Or does it seem to be coming from below?
Taking 20 minutes to warm up is definitely a hint.

Thx so much for your help! There is no vibration on the driver side. The sound is throughout the car, but sounds a little louder on the passenger seat area. We can’t figure out exactly where the noise is coming from. I’ve never stuck my head out of the car to see if I can hear it from outside as we are usually on the highway. I’ll try that the next time. Once the noise starts, it doesn’t stop. So, for the first hour of a 10 hour drive we didn’t hear anything and then once it stated, it didn’t stop for the next 9 hours. Even when we stopped to get gas and eat, we started the car back up and then noise came back on within 15 minutes. Thx again!

As you can imagine it is difficult to diagnose over the net.
From an interior noise perspective, finding an automotive stethoscope may help to pinpoint the rattle noise along the passenger side dash area if it is interior.
In the video, do you have the blower fan on, if so turn it off & do another video.
If it is an external rattle, get it up on the lift and it's inspection time.
Look for anything loose or rattling in the exhaust or cats & clamps etc.
A good mechanic after a test drive will be able to hear it and hopefully have a better feeling of what may be going on.

The GMC mechanic road with me and was clueless, but heard the noise so he knew I wasn’t off my rocker. Then they kept my car for a week and a half and said they couldn’t duplicate the noise and so they couldn’t fix it. The noise doesn’t always go on...so I understand they couldn’t duplicate it—they drove it a total of 70 miles according to my speedometer. I’ll look into a stethoscope—didn’t even know those existed. :) Thx again for all your help.

The symptoms:

- Cold to hot takes an hour
- Warm to hot takes 15 minutes

. . . makes me think exhaust system or exhaust system adjacent.

Thx so much for your help! All of it is so appreciated as I’m clueless when it comes to cars.