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Sound of rushing air

Yahoo Message Number: 100421
2002 Intrigue 36-foot. While driving on the Interstate there was suddenly a very loud sound from the right rear of the coach that sounds like rushing air. It continued for about a minute or two and then the sound tapered down and went away. First thoughts were the air pressure system but the air brakes work fine, the air leveling is working fine, both the red and green air pressure indicator needles on the dash are reading 120psi, tire pressures and temperatures are all reading OK, and the ISL370 engine seems to be running normally. From inside the coach the sound appears to be coming from the vicinity of the right rear wheels (no tag).
 The sound went away and all was fine but came back again several times starting off loud and then fading away. While the sound is happening it doesn't correlate to road speed or engine speed. It does seem to come back when we are climbing. We have been told in the past that we have a very slight leak in the Charge Air Cooler (CAC) and if it failed we would know it by the loss of engine power but no loss in engine power or performance is evident. Would there be a noise like I've described if it was the CAC? Any other thoughts?

Steve

2002 Intrigue 36' #11382

Re: Sound of rushing air

Reply #1 –
Yahoo Message Number: 100422
Sounds like air dryer purge is stuck open.  You might not notice on gauge if it's open for just a minute or so. And they do sound like it tapers off as compressor changes state or emergency air tank is emptied.
I think we have check valves in the air tanks. Air may be escaping the emergency tank and you would not see it on your air gauge.
 If purge valve they are easy to change. I did it on the side of the interstate in Kansas.
Nate 1998 Allure, Indianapolis

Re: Sound of rushing air

Reply #2 –
Yahoo Message Number: 100423
My first thought is the fan kicked on high, especially when  you added it happens most when climbing.

Ray

They say wine improves  with age! As I enter my golden years, I say age improves with wine!  The Born  Loser

Re: Sound of rushing air

Reply #3 –
Yahoo Message Number: 100425
Steve,

The first thing I would check is to see if you have lost one or more of the window seep hole covers. That happened to me and it did make quite a bit of noise.

Jock vargo

2005 Inspire
51428

Re: Sound of rushing air

Reply #4 –
Yahoo Message Number: 100426
Reply to Ray - Fan is a good thought but the sound is very concentrated on the right side and the radiator and fan are on the left side. Thanks for your input. Steve

Ray wrote -

My first thought is the fan kicked on high, especially when you added it happens most when climbing.

Re: Sound of rushing air

Reply #5 –
Yahoo Message Number: 100427
Reply to Nate Blackwell - I'm trying to wrap my head around the relationship between the air dryer purge valve and climbing a grade. When we pulled over and I went out to see if there was anything that seemed out of the ordinary, the engine was running and the purge valve popped as it normally does when the air pressure reaches max. If it would stick open, wouldn't I hear air rushing after the pop? Or am I confusing the purge valve and the check valve?

Nate wrote - Sounds like air dryer purge is stuck open.  You might not notice on gauge if it's open for just a minute or so. And they do sound like it tapers off as compressor changes state or emergency air tank is emptied.

I think we have check valves in the air tanks. Air may be escaping the emergency tank and you would not see it on your air gauge.

Re: Sound of rushing air

Reply #6 –
Yahoo Message Number: 100428
If the purge valve was stuck open you would hear the air leak at idle. I don't know if you could hear it at speed. I had a purge valve stick, I discovered it at idle and unstuck it with a rap from the flashlight. it worked fine for about 1000 miles when I changed out the canister and purge valve. I did note that the new purge valve was heftier than the one taken out. If you haven't changed these in the last 30-50K miles, it might be a good idea to do it now.

John Beach

06 Allure 31309

Re: Sound of rushing air

Reply #7 –
Yahoo Message Number: 100429
If dryer purges when called for and sounds normal then you are probably right it's working as intended.  I kinda disregarded the climbing grade as a coincidence.
My dyer actually went bad. When at idel the purge valve would dump as normal. When under way it would purge and stay open on occasion and we lost all air in the wet tank. Still had air for brakes thanks to the check valve at the tanks not letting air back to open purge. However no air was getting to the bags and we quickly had a harsh ride.
A quick test to rule out the dryer is to simply bypass it. On ours it was simple with monkey wrench. Took me hours to figure out our problem and eventually just replaced dryer and purge.. If you can bypass dryer and travel one could at least rule it out.
When that purges stays open you hear it it's loud.
Airbag leak, airline leak, bad air governor at air compressor, ......
Nate 98 Allure

Re: Sound of rushing air

Reply #8 –
Yahoo Message Number: 100430
Continuing down the road the problem has worsened. The noise would occur with every incline in the road. Then along with the noise we began getting engine bucking and a periodic flash of the "engine warning" light so we got ourselves into a rest stop out in the middle of nowhere and began making calls. Country Coach Tech Support said it could be the CAC or the Turbo charger or something else so we called Coach-Net for a tow. We'll be towed to Great West Truck in Needles, CA for repair. Hopefully they can resolve our issue. Not happy about a tow from the front rather than a flat-bed tow but they will be disconnecting the drive shaft and hooking up air to keep our rear end off the ground. Wish us luck.
Steve

2002 #11382

Re: Sound of rushing air

Reply #9 –
Yahoo Message Number: 100431
I'm sorry it wasn't compressed air!! Wish you speedy repairs then trouble free miles.
Nate

Re: Sound of rushing air

Reply #10 –
Yahoo Message Number: 100445
Status update - We did get a flat-bed tow after all. First truck couldn't tow us because we have IFS and not a solid front axle and he didn't have the equipment to pick us up by our front wheels. Towed to Great West Truck in Needles, CA. Great crew! Found broken flange on Turbo Charger exhaust tube. To speed things up we drove 4-hour round trip in our Jeep to Las Vegas to pick up parts. New flange cut and welded in place and we were on our way 25 hours after initial problem.

That was the good news. 50 miles later while pulling a grade we got an engine warning light and reduced engine power. Called Great West Truck in Needles for recommended service in Kingman ... another Great West Truck center but much larger. We limped to that facility, got diagnosed with a fuel pressure code, changed out the fuel filters, and found lots of dirt, quite possibly algae. I've been using an algaecide and keeping the tank full, but those little buggers have a way. This happened several years back and I was cleaning and changing filters frequently until the debris was all cleaned out. I do carry spare filters.

Now on the road again with several hours and several long steep grades behind us so hopefully those problems are also behind us and we'll make it to my reunion in Philadelphia.

Steve, 2002 Intrigue #11382

Re: Sound of rushing air

Reply #11 –
Yahoo Message Number: 100446
Good news and it seems once your fuel tank have been polluted you have to be prepared for it to happen again and again.  So I always carry extra filters. And a gallon of fresh clean fuel.  TWI 2004 Intrigue 11731.