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Discussion Starter · #1 ·
Ok... May sound wierd.....since I've had this car (a little over a year) there has been a noise coming from the dash area on the passenger side when I accelerate and decelerate. No noise while coasting or after initial pressing of pedal.

Not quite sure how to describe, other than it sounds like something is pressurizing when accel. (pssshhh...like a hospital re-breather?) :confused:

Heat blows hot and consistent at all times when demanded, and A/C blows cold and consistent when demanded. All fan speeds work. No change noticed in fan speed during the noises.

I just looked through all 18 pages of threads on the HVAC forum here, and didn't see anything described quite like this. Any ideas before I start taking stuff apart, and suggestions on disassembly are greatly appreciated! Thanks!
 

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Could be a vacuum leak. Do all the HVAC doors actuate in the airbox - floor, vent, defreost? Even if they do, could be a leaky hose. But only on acceleration..................?
 

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Discussion Starter · #3 ·
Could be a vacuum leak. Do all the HVAC doors actuate in the airbox - floor, vent, defreost? Even if they do, could be a leaky hose. But only on acceleration..................?
Yeah... it IS wierd... everything works great... the HVAC doors operate properly and the air moves great hot and cold.

If I let off the gas and press down again, the noise happens each time. Doesn't seem to affect anything, but it is one of those things...It's not SUPPOSED to make that noise so it's really buggin' me! :) It's like a MONK thing... just wanna fix it. :D
 

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Put this in the engine section........ let those gurus have at it. Could be under hood but sounds like in the dash. A better description might help - get a second opinion. If you are convinced it is in the dash, get a passenger to monitor with a stethoscope. We don't want you to go crazy.
 

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Does it sound like an air leak (vacuum leak) or a gurgle or waterfall sound (air trapped in cooling system)? Vacuum leaks are usually noisiest when decelerating or coasting (high engine vacuum), trapped air is usually most noticible at high RPM's.
 

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Discussion Starter · #7 ·
Does it sound like an air leak (vacuum leak) or a gurgle or waterfall sound (air trapped in cooling system)? Vacuum leaks are usually noisiest when decelerating or coasting (high engine vacuum), trapped air is usually most noticible at high RPM's.
The best way I can describe it is "like air filling a small balloon" when I press on the gas and deflating when letting off(and only WHILE I press down and let go of the gas.)

It is behind or under dash on passenger side. My fiance really wasn't any help, and she is the one that is closest to it unfortunately.

I'm gonna have to let a friend drive it while I lay upside down in the passenger seat with my head stuffed under the glove compartment going down the highway. I'll make sure I get some pics... LOL
 

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Ah yes.....the infamous "waterfall" sound.

If you have heat and no air is trapped in the system.

I will bet that your drain elbow is miSSing.

Check paSSenger side under the hood where heater core hoses go in and come out of the firewall, you will see a pipe sticking out to the left of the hoses down low, that is the drip tube and will have a rubber 90 degree elbow on the end of it (in this case you wont see the elbow as its prolly gone).

You can get an elbow from any dealer for cheap (Part number: 22542866).

Oh yeah, when you put the new elbow on there look up the "drip tube mod" for preventing the AC drip water from pooling around and onto the ABS sensor that is located directly below it.
 

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i have the same exact problem with my car. when you figure it out let me know please, also just curious when youre ac is on does it feel like your ecar has a slight miss to it when cruising speeds? just curious.
 

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The vacuum tank for the HVAC system is in that exact location, just left of the passenger airbag, could be a leaky feed line as well, there is a black line that comes in through the firewall to a green vacuum connector or splice that ties into the system and feeds the vaccum tank, I would look there.
 

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You could disconnect and plug (on the engine side) the vacuum line from the engine to the HVAC. If the noise stops, it is in the HVAC. If not you have eliminated the vacuum system, as a culprit.
 

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You could disconnect and plug (on the engine side) the vacuum line from the engine to the HVAC. If the noise stops, it is in the HVAC. If not you have eliminated the vacuum system, as a culprit.
this.
if theres a vacuum leak or the vacuum check valve is gone or stuck open the hvac doors can move under full throttle when the vacuum drops.
 

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search my topics, I had the same problem and snapped a pic , ended up being a vacuum line directly behind the airbag, you can't see it but can feel it with hand with dash removed.

if I remember right violet and black line run to this vacuum tank and there's a diagram on shbox.com
 

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search my topics, I had the same problem and snapped a pic , ended up being a vacuum line directly behind the airbag, you can't see it but can feel it with hand with dash removed.

if I remember right violet and black line run to this vacuum tank and there's a diagram on shbox.com
Yes black is the feed to the tank and violet is the feed to the mixer valve.
 
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