Humming sound on my Prevost/liberty...anybody every experience this

[statedrive]

I have a 90 Prevost/Liberty and it started making a sound (like blowing over an empty soda bottle) when
we get to 35 MPH and higher...it goes away when a trk passes and gets in front of us for a short time..
any ideas...thanks  Dave

[H3Jim]

I'd get out on a ladder and look for anything that might do that, such as a missing cap over a tube of some sort.  If its coming from the front, then you would just check the entire front etc. 

Sure seems wind related, via the speed thing and follwing a truck etc. .. but you knew that.

[WEC4104]

Also agree.  Here are a couple of additional thoughts..

- When did you start noticing the sound and has anything changed on the exterior (added an awning or antenna?)

- While driving, have you had someone walk around the inside to try and pinpoint the direction the sound is coming from?  I would expect you should at least get a front/rear determination. The higher the pitch of the sound, the easier it will be to directionally locate.

- With a sound like a soda bottle, I would pay special attention to any circular openings.  These could include roof vents for the holding tanks, and the generator exhaust pipe. A lower pitched sound means a bigger opening/cavity. If you temporarily tape them closed and go for a drive you can start a process of elimination.

- I would also go through the entire coach and open, then re-close, every window and door I can find. This include ceiling vents. Check for loose window screens.

- I'd carefully inspect the coach for elongated strips of loose material, such as plastic trim pieces around windows, wiper blades, or possibly awning straps.  When air is forced over these long strips they can act like the reed of a musical instrument and "sing".

- Lastly, I think I'd check for that empty St. Pauli Girl I tucked behind your front bumper.

 

[JohnEd]

I think you are hearing your own heart beat with pride at owning one fine fine bus.   Either that or you are fabricating this problem to draw attention to your owning a fine fine Pre.   One or both.   God, I wish I had your problem....snif...wine...sniff.

John

[Gary '79 5C]

Is your entry door closed tightly, mine was not sealing tightly and produced similar sound.

Good Luck

Gary

[Busted Knuckle]

I'd just trade it in on a SETRA!  HMMM guess what I got the perfect one for ya! A '91 model very strong 8V92TA / 748 Allison can be completely stripped and a bare bones shell by the time ya get here! Just let me know when ya wanna trade and "I'll get'r done for ya!" LOL!      BK 

OK if not maybe try some of the above suggestions! Altough the offer still stands!

[Charles in SC]

I had something kind of like that on my GMC. A piece of aluninum trim was loose at the front and would blow out in the wind and make noise. Only took me 4 or 5 years to figure out what it was. The fix was easy, just re-riveted the front end back in place.
Good luck!