Buzzing in the front of 2020 Hurricane

[Vibeman]

We have a 2020 Hurricane 29M that has a bothersome buzzing noise above 40 mph. As near as my wife can tell while seated in the passenger seat, the noise is coming from the lower right front corner. It is difficult to pinpoint but seems loudest at the right hand kick panel under the dash. This is where the sound system speaker is located but I’m pretty sure the noise is not coming from the speaker itself. The noise is definitely speed/wind related and even changes slightly depending on outside wind direction. It also modulates a lot when we are close enough behind a semi-truck to be in his slip stream.
I have been experimenting by stuffing towels in the various cavities behind the grille and also by putting masking tape around all external seams that are in the wind flow. Since this is the area where the chassis heater is located I have also experimented with all heater/ac settings. So far this has all had only a very minimal effect, or maybe even no effect. I am now in the process of stuffing and masking features inside the R/F wheel well. I WILL find the problem eventually but I am posting this just in case someone has the same problem and has already solved it. I have found other threads here about wind noise and as near as I can tell they are all relating to a high pitched sound. This is definitely NOT a high pitched sound and definitely IS speed related, and can only be described as a low frequency “buzzing”. It could very well be something unique only to our coach, such as a loose panel or some other component. Thanks in advance for any help.
-Ken

[RV Pirate]

Gonna be hard to diagnose that one in here. I'd start looking around outside nearest your best guess of where the noise is coming from. Could be a piece of tape or production tag somewhere, loose zip tie, etc. Good luck

[MJC62]

I agree with the Pirate awful hard to diagnose on a forum. I do believe you are on the right track chasing wind noise. Our ACE has a wind noise in the grill that is more of a whistle at around 40 as it goes away at higher speeds I haven’t been too worried about chasing it down once I realized it was wind noise and parts weren’t coming off. It can be annoying for the occupants so I feel your pain! Good luck with your hunt. Mark

[Vibeman]

Update:
After a lot of experimenting with no success I finally removed the entire Fiberglas front panel and.....the noise is gone. I have contacted Thor about this and I will report any progress here.

[Delscorcho]

We are having the issue.

We have a 2019, Hurricane, 29M.

The buzzing noise starts around 40 mph and is definitely speed / wind related. Our noise sounds like its coming from the upper drivers side area. It is very annoying.

Did you figure your problem out? What fiberglass piece did you remove?

Thanks.

[Vibeman]

Update:
I took the Hurricane back to the dealership last summer, they spent significant time stuffing, taping, sealing, and test driving. They got the noise reduced to where it was only barely audible (but still there) After all that they were still baffled as to the source. It still comes and goes according to wind and weather conditions but is now mostly ignorable and endurable. This summer I plan to pull some or all of the interior dash panels off and seal/insulate wherever possible or practical. Hoping to decrease general road, engine, and wind noise and maybe eliminate the buzzing in the process.
The panel I pulled off was the vertical fiberglass hood which gives access to the engine. With the hood removed the noise was totally gone at all speeds. Although I think that was due to its effect on air currents in the engine compartment and under the dash, not the hood itself
-Ken

[broncoboy]

Just purchased a used 2020 Hurricane 29M with 12,500 miles. Took it on our first trip of roughly 300 miles yesterday. Same exact buzzing issue that you’re describing. Right behind/under the driver dash. It started happening about half way through the trip. Starts up at about 40/45 mph and is definitely speed/wind related.

Super annoying, but I suppose if it’s not a mechanical failure and just something wiggling I’m not too worried about it. I would like to get rid of it though. If you have any luck please update us!

[Vibeman]

I am in the process of installing sound deadener and insulation every place I can right now. Since my previous post we have driven over 1000 miles and the noise has not increased. At this point i’m not sure if I will ever know the root cause. But sealing and insulating under the dash in the engine compartment has almost eliminated it.

[Vibeman]

Follow-up:
I bought a box of Noico sound deadener and a box of Noico Red sound insulation and spent 3 days with my head under, over, inside and outside of the dash and engine compartment. I put the Noico aluminum faced sound deadener on all surfaces of the under dash and firewall that are accessible from the engine compartment. I also used Gorilla tape where needed. This was the hardest part, kneeling in front of the engine working overhead. This was also where the dealership spent most of their time (see my previous post) so many of the gaps were already filled.
I disassembled as much of the interior dash as I could without removing the instrument cluster, I also pulled out the radio, and I cut and stuck panels of the Noico deadener and Noico Red insulation material sandwiched together on the back side of all of it. I also put it on the interior side of the firewall where I could, mostly in front of the drivers seat.
I bought a bale of "Safe and Sound" rock wool bats and I filled all under dash cavities that did not contain electrical components. I also used a can of the expanding foam sealant wherever I needed to fill narrow cavities (like under the defroster plenum) and also used Gorilla tape to seal gaps and cracks. The vertical pillars on each side of the windshield were a source of wind noise but the plastic covers were not removable without total removal of almost everything. They are only stuck to the walls with double sided tape but locked in at the top and bottom by other components, so I was able to pry the tape off the wall paper (some was already unstuck) and pry and bend the plastic panels out far enough to slip pre-cut panels of the Noico behind and stick them to the back of the interior panels. I also poked in some rock wool to fill the cavity.
I had already installed a double layer of Dynamat hood liner under the doghouse cover last year so I left that as is but I removed the cup holder off the top of the doghouse and put Noico under it.
I purchased the heavy basketweave patio mats at Lowes as others have done, although I bought two of them, I removed the seats and completely covered the cockpit floor with only one small seam in the middle under the table pocket.
We took it for a test drive yesterday and the improvement was amazing! Still not a Rolls Royce levels but MUCH better than before. PLUS THE BUZZING NOISE WAS TOTALLY GONE AT ALL SPEEDS!!! This was just a 30 mile test drive but we are leaving on a 500 mile trip in a couple of days for a full test.
I am pretty meticulous and took my time when cutting and fitting all the Noico so all surfaces possible were covered well and stuck down securely. It was a lot of work but now that it is done I am glad I did it, and I now consider my soundproofing project completed!.
BTW, I had to purchase a whole bale of the rockwool but only used 2.5 panels so if someone wants to stop by I will give them a deal on the rest.
-Ken

[Patawan]

I have a 20/20 Fleetwood Fortis with the same problem. I discovered that they have used self-adhesive weather strip or two-sided tape to attach parts of the grill to the front end cap. I found the bottom of mine had come loose and the glue had all dried out and the weather strip had failed. Causing the lower grill to vibrate against the end cap causing a resonant buzzing inside the RV. Spent $6 at home Depot for new self-adhesive weather strip, cleaned the bottom of the grill, reattached weather strip and as a safety measure tapped three small holes from the grill into the end cap and put three small stainless steel screws there. Problem solved

[Johng]

to build on the last entry in this thread. i believe we have the same issue after recent work after hitting a deer last june. we had the factory install a new front cap and engine cover. we finally got the rig back in early january and noticed the noise at speed. the new grill cover over the engine is very flimsy and only mounted on the top edge of each fin. i will add double stick sealed foam tape to solve. the original cover was thicker and firmly mounted and we had zero noise. i already added 5 screws to dash area they left off when reattaching front cap. the dash itself was attached to cap with expanding foam on the front edge.
i had already cleaned out the side windows with air compressor and lubricated the tracks. this eliminated alot of noise. we headed out for a 10 mile round trip thursday. 100% quiet going east, turned around and headed home 100% loud over 40 mph to 70 mph going west. roads were dry but it is still below freezing around here.