New 580 owner experiencing a relatively loud thump coming from the interior when the rear tires travel over medium-to-large bumps. Car is brand new and began this behavior almost immediately (picked up the car last week with seven miles).

Conducted a search before posting, and per the one thread I did find, I don’t think it’s the rear hatch lock. I also tightened the spare tire mount, checked the cargo cover, and other obvious bits. Not certain, but the sound seems to emanate from above (possibly the panoramic moon roof?).

Taking it to the dealer Friday but thought I’d check here for any relevant insight. Anyone experience anything similar?

Thanks in advance.

 

You can try removing the tonneau cover to see if it makes a difference. There's a storage spot for it above the spare tire (if you have one).
Perhaps it wasn't put on properly?

 

Good thought; I will remove it completely from the vehicle and give her a test drive. Eliminating every variable is a great idea.

However, it does seem as though the thump is coming from overhead.

Thanks for the reply!

 

I lowered my tire pressure to 31lbs all around per the gas door chart and it definitely helped the bumps.

 

Closing the loop: took the GLS to the dealer and was able to reproduce the sound for the shop foreman. Approximately seven hours later, the SA called stating the issue had been resolved.

According to the SA, the issue was “caused by the sunroof screen bracket moving and hitting the metal support on the sunroof glass.” The solution involved adjusting the screen bracket bolts, applying noise damping felt, and adding additional insulation. The ride home was quiet and thump-free, in spite of my attempts to hit every bump possible. As my SA said, “I hope we don’t see each other for a year or 10k miles, whichever comes first.”

As an aside, the dealer gave me a new S580 as a loaner, and I was not impressed. While the ride and engine power were nice, the interior didn’t seem worthy of MB’s flagship vehicle. The materials were cheap looking, particularly the “wood” and piano black trim. The “wood” slab across the dash was so fake looking it wouldn’t pass in a $30k Nissan. The large swathes of piano black trim covering the center console and door panels were covered in fingerprints and cheap looking in a $140k car. The tech was slightly above average, but the lack of physical buttons was frustrating, and the center screen seemed an afterthought (my wife said it looked like the MB engineers glued an iPad into the dash). Just my $0.02; not meant to offend anyone who might appreciate the S-class.

 

It sounds like you have a great service department at your dealer.

 

Yes, I was very impressed with them.

 

My dealer's Service Department is the reason I drive a Mercedes. And the one before that....
And I drive an hour past the closest, for the Service.

Their Sales Department is a different matter....

 

Totally agree. The service department is more important to me than sales when selecting a brand and a dealer. I fully expect shananigans and deception from the sales department, but the service department can make or break the ownership experience, and be the deciding factor in purchasing from that brand again.