Noise from front corner

[jgreen]

I just came back from a short trip (400 miles) and part of the way back I started to hear a noise coming from the front passenger side corner. It sounded like a valve opening or closing and a hammer noise. There was no sound of air being released and it sounded more like the bar door locks when they engage. It would only happen every few minutes. After about an hour I closed the front shutters (from the dash switch) and didn't hear the noise again. After about 30 minutes I opened the shutters and the noise started again. Any ideas?

Not sure if its related but I just had all the air bellows replaced.

[Dtjoint]

We had a mysterious noise and vibration coming from the front passenger side that sounded and felt like a damaged wheel or tire. Finally determined the cause was the front heat exchanger fan vibrating at a certain speed. We were driving in a strong front wind. Not sure about the cause but it was replicatable under those conditions. Have not heard/felt that again. Any chance that fan might be the source of your odd sounds?

[jgreen]

That could be the cause. There was high winds yesterday and closing the shutters stopped the noise. I didn't think about the front fan.

[Gil_J]

Aren't the shutters suppose to be closed when driving for better cruise air performance?

[truk4u]

Shutters should be open while driving if cruiseairs are being used, otherwise keep shutters closed for less cold air to driver passenger air. When parked and using crusieairs, shutters open.

Shutters closed while driving and using Cruiseair will hi temp and shut down if ambient temps are high.

I seem to remember some model year changes that may have change some of those procedures.

[Gil_J]

Tom, that makes sense to me. But more than one Liberty XL owner has told me otherwise.

[jgreen]

Tom, Thanks for the input on the shutters. I don't use the crusieairs when driving because I have the bus air, but I wasn't sure if the shutters should be open or closed normally when driving.

[Ben Neumann]

James,
I also have a 1998 Prevost but was converted by Country Coach. The noise would start every time I exceeded 35 MPH. It would start vibrating the whole front dash and made a terrible loud noise. To find the source of the problem, I purchased an electronic noise finder with 6 microphones which I attached to numerous valves and other areas in the bay below the driver. While these microphones were attached during driving I found the problem immediately. It was the snorkel of the front AC evaporator drain. This snorkel would open and close at a high speed and create this high frequency noise. Cut the snorkel off and stuffed a little bit of fiberglass into the hose and problem solved.
Ben

[Dtjoint]

One more wierd one to check. When we first purchased our coach I heard what sounded for all the world like wind noise from an open duct or channel. it was only apparent while driving and I could not find the source until digging in behind the dash I found a speaker not related to the annunciator system CC used. I disconnected it and the noise went away. Hmmmmm. Turned out to be the speaker for the microphone in the backup camera. It was picking up engine and road noises. Pilot error problem solved.