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Hyundai Sonata Rear Thump

silverfox1silverfox1 Posts: 91
edited March 7 in Hyundai
Have a 06 Sonata LX. Chasing above average rear body/ chassis thumping when going over a bump or step in the pavement. Have relocated the spare and tighten the holding mount. Re adjusted the two trunk stops. Securing the spare helped but still have some thumping. Is it possible that some added padding to the trunk floor will help? Anyone have the same problem and a solution?


  • Silverfox1:

    I have a 2006 Sonata GLS 4 cyl. I hear a slight knock or bang (I think coming from the undercarriage) often times when I first accelerate. Does anyone else have this?
  • tb88tb88 Posts: 242
    May be it's the fuel used causing knocks!
    Switching to a different gas station / higher octane may solve the problem... Old gas stations sometimes have storage tank problems (water/contamination...).
    I always try to get Gas at the newest gas station around.
    I also read, that some new 4cyl cars require Premium (i think i read that in a Civic Si review!!
  • No problems with noise from chassis or body on take off. Thumping occurs when driving on bumpy roads. Car is very quite on smooth roads. 17" tires do not help the thumping issue since they have very little give to them. I think added insulation and better quality bushings between the chassis and body would help. Anyone out there have any thoughts on this problem?
  • Thanks tb88 for the reply. Don't tell me that - last thing I need to do is buy premium gas. Hopefully it will stop.
  • Hi Silverfox, is the noise definately coming from the spare tire well or is it from one of the rear wheel wells? Just curious,
  • Sounds seems to come from the lower trunk area which makes me think the suspension is not isolated enough from the lower body. Car is so quiet on smooth pavement any noise is offensive. Will review issue with dealer some time in the future. Do you have a similar condition?
  • cxccxc Posts: 122
    I noticed similar condition for my 06 Sonata LX. It turned out that the fold down rear seats were not locked as the car came out the factory. After locking the rear seats from trunk, I did not hear any abnormal sounds from the rear. I hope this will help.
  • Thanks for that info, will check that out in the morning. I been playing mind games trying to figure out what and where it is coming from. I was thinking of the exhaust system as it seems more pronounced when the car is cold but may be my imagination.
  • Silverfox1, I work for Hyundai in quality control. I'm not here in an official capacity though (hence the 007)

    If I understand you correctly the noise is coming from the rear suspension when you go over a sharp bump or step? Sounds like rear hub noise to me. Tell your dealer service that you suspect you have rear hub noise and that you may need your e-brakes adjusted. At least sitting here that may be the issue.
  • Thanks for the reply. I have an Sonata LX with rear disks. I believe I may have found some of the problem. I think the cover for the spare moves vertically and may have a drum affect. I went over a sharp bump yesterday (rail road tracks) and it sounded like came from that area. I had repositioned the spare and tighten the holding hardware for the spare earlier so I know that area is secure. I also have locked the rear seat backs from the truck. Will try to secure the spare cover (trunk floor cover)to see if that has any improvement on the drumming.
  • Hmmmmm that's odd that there's noise from the spare tire cover. I won't say what part of QC I work in because that would narrow me down too far, but I've never heard that as an issue. I'll keep a lookout for that in the future. I know this sounds silly, but is the spare tire cover turn the right way (litle pull handle at the rear) and is the trunk liner pulled over the rear seat "flaps"?

    Hyundai road tests all cars thoroughly for noises, quality and safety issues.
  • Just checked my trunk and see that the trunk cover is over the rear seat cover. Also the spare cover is correct with the tab to the rear. Interesting that the two rectangular slots that accept the spare cover tabs (two) do not have any means to latch or hold the cover in place. Should there be some type of clip mounted on the rectangular slots to catch these tabs?
  • Still fighting this excessive thumping noise when going over bumps on my 06 LX. Starting to think that the oversize trunk resonates with the suspension on bumps. Any thoughts on that theory?
  • tb88tb88 Posts: 242
    All you have to do to find out is to fill up the trunk with something, preferably with something that wouldn't bounce and make noise: Blankets/pillows/foam/ etc...
  • I recently purchased the '06 Sonata LX, and I am experiencing the same rattle/rumble thumping noise in the rear passenger hub area!!!!

    The service department said everything was working to Hyundai specs (they had a "Hyundai engineer" test drive it with me and he said it was normal road noise - baloney), and the general manager said he is trying to get Hyundai to address the issue, but to no avail.

    It occurs on bumps and dips usually below 30 mph. It is especially loud under 5 mph when you go over a bump or dip.

    There is also a constant droning/resonating hum noise when the car hits about 30 mph and higher, which is most noticeable on concrete.
  • I have looked into several approaches to reduce the rear suspension noise starting with the most cost effective one first. I purchased some top of the line carpet padding and placed it between the trunk carpet and the body pan. This helped with reducing some of the high frequency noise and some what reducing the rubble sounds. The better solution is to invest in the rubber/alumium wrapper material that the audio people use to reduce the resonance when installing those large base speaker systems. I checked into it and a 12 foot square of this material was $96!!!!!!!!!! To do it right you should do the trunk and rear floor area's. Not ready to spend this kind of money to cover a design problem. On the concrete noise issue, "haefr" is right on the money. It certainly is a tire tread issue. I have a new interchange near me and those Michelin Pilot tires do make noise on it. My Continentals on my old VW GTI did the same thing. Let me know if you get and help from dealer on the rumble issue.
  • If you want to try something on the trunk of the Sonata to reduce the noise level and don't want to shell out for Dynamat, BrownBread, etc try some Ice Guard or similar material at your local Home Depot or wherever. It's made for weatherproofing/insulating your roof but it makes a pretty good soundproofing material and you can't beat the price or availability. I use it in place of Dynamat and the rest for certain installs.

  • stealth6stealth6 Posts: 13
    Try tightening down the spare tire. I mean really tighten it down!
  • mamamia2mamamia2 Posts: 698
    The "thumping" noise, known elsewehere as K-Thunk is a problem of the V6 models only, and seems like it is typical to the '06 model cars only, and apparently was fixed in the '07 cars.

    The latest info published, unofficially though, is that the cause of the noise is the REAR SUSPENSION, and that Hyundai is now working on a fix that's suppose to be in the shape of a RUBBER seal that needs to be added to the rear shocks. Stay tuned.
  • Hello happy owners of sonata. I am thinking of buying sonata 4 cyl. with manual transmission and I'd like to ask you how good and reliable this transmission from your experience. How easy it operates, how you like the clutch performance, what engine rpms you have at 120 km/h. and how quiet a car at this speed. Thank you for any info on these questions. Enjoy your cars
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