Whirring Sound, WHAT IS IT? watch you tube video

[2000GotBoxS]

Hey Folks,

 

Take a look at this video I posted to you tube, 

   What do you think this is?  The sound seems to go away when I turn the AC off, but, I have heard it when the AC is off before.  It goes away when I step on the gas too.  It seems to be there in lower RPMs, and I can't quite place it.

 

It sounds like a sucking or whirring sound.  I am not quite sure whether it is coming from the cabin air cleaner, the charcoal canister underneath, or from the fuel tank.

 

Its strange that it goes away when the air is turned off and when I change the RPMs.  Its most notable at steady RPMs below 2000.  I've never heard it above 2000 rpms.

 

WHen the sound goes away, I am actually reaching into the car and turning the air off.  If you listen closely, you can hear it start sucking again, and slowly ramping up to that whirring sound again.

 

Any ideas??

Edited June 27, 2015 by 2000GotBoxS

[JFP in PA]

Hey Folks,

 

Take a look at this video I posted to you tube, 

   What do you think this is?  The sound seems to go away when I turn the AC off, but, I have heard it when the AC is off before.  It goes away when I step on the gas too.  It seems to be there in lower RPMs, and I can't quite place it.

 

It sounds like a sucking or whirring sound.  I am not quite sure whether it is coming from the cabin air cleaner, the charcoal canister underneath, or from the fuel tank.

 

Its strange that it goes away when the air is turned off and when I change the RPMs.  Its most notable at steady RPMs below 2000.  I've never heard it above 2000 rpms.

 

WHen the sound goes away, I am actually reaching into the car and turning the air off.  If you listen closely, you can hear it start sucking again, and slowly ramping up to that whirring sound again.

 

Any ideas??

 

Probably a leak somewhere in the EVAP system.

[2000GotBoxS]

 

Hey Folks,

 

Take a look at this video I posted to you tube, 

   What do you think this is?  The sound seems to go away when I turn the AC off, but, I have heard it when the AC is off before.  It goes away when I step on the gas too.  It seems to be there in lower RPMs, and I can't quite place it.

 

It sounds like a sucking or whirring sound.  I am not quite sure whether it is coming from the cabin air cleaner, the charcoal canister underneath, or from the fuel tank.

 

Its strange that it goes away when the air is turned off and when I change the RPMs.  Its most notable at steady RPMs below 2000.  I've never heard it above 2000 rpms.

 

WHen the sound goes away, I am actually reaching into the car and turning the air off.  If you listen closely, you can hear it start sucking again, and slowly ramping up to that whirring sound again.

 

Any ideas??

 

Probably a leak somewhere in the EVAP system.

 

Do you think its a leak or is it the fuel line vent valve??  Also, i understand why the sound goes away when I step on the gas, but, why on earth would it stop when I turn the AC off?  That makes no sense to me.  JFP, can you shed any light on that for me??  Thanks Buddy!

[JFP in PA]

 

 

Hey Folks,

 

Take a look at this video I posted to you tube, 

   What do you think this is?  The sound seems to go away when I turn the AC off, but, I have heard it when the AC is off before.  It goes away when I step on the gas too.  It seems to be there in lower RPMs, and I can't quite place it.

 

It sounds like a sucking or whirring sound.  I am not quite sure whether it is coming from the cabin air cleaner, the charcoal canister underneath, or from the fuel tank.

 

Its strange that it goes away when the air is turned off and when I change the RPMs.  Its most notable at steady RPMs below 2000.  I've never heard it above 2000 rpms.

 

WHen the sound goes away, I am actually reaching into the car and turning the air off.  If you listen closely, you can hear it start sucking again, and slowly ramping up to that whirring sound again.

 

Any ideas??

 

Probably a leak somewhere in the EVAP system.

 

Do you think its a leak or is it the fuel line vent valve??  Also, i understand why the sound goes away when I step on the gas, but, why on earth would it stop when I turn the AC off?  That makes no sense to me.  JFP, can you shed any light on that for me??  Thanks Buddy!

 

 

Because of the location you indicated, it can only be one of two things:  The EVAP system, which is just below the fuel filler door area, under the wheel well liner; or possibly the AC coil in the heater box, which is adjacent to the EVAP system behind the firewall.

 

You need to get a stethoscope and try an isolate which one it is,  By far, most of the noises we see in this area are from the EVAP system (stuck valves - there are multiple, leaking hoses, canister itself,  etc..).  As this would be a vacuum leak, it will change volume or vanish with RPM movement.

[Loren]

I suspect there is at least one fault code if you scan with a Porsche diagnostic tool...

[2000GotBoxS]

Hey Loren, thanks for the reply, unfortunately, there are not any fault codes, and no CEL.  That's what has baffled me.  I would have thought for sure that I would have thrown a code for the EVAP system.  I was leaning towards the AC system, as I have recently found little pieces of some sort of foam sealing substance in my air vents.  The lack of a code, and those small pieces of foam insulation or sealing stuff had me thinking that air was possibly leaking around the cabin air cleaner, but, that wasn't the case.

 

Until recently, I was not able to duplicate the sound unless I was driving slow, with engine RPMs at around 2000.  Making a stethoscope virtually impossible.

 

But, now it does it sometimes at idle.  I will try to duplicate it at idle and get under there with a stethoscope and see what I can figure out.  I will post my results.  This seems like a common problem, as I have seen posts on the Pelican Parts site as well.  So, I'll follow up here when I figure it out and maybe that can end up helping someone else down the line.

 

Thanks JFP and Loren.......

 

B

[Loren]

The disintegration of foam in the HVAC is pretty normal for a 15 year old car. I would not worry about that being the cause unless the noise goes away when you turn the AC and the inside fan "oFF".

 

What diagnostic tool did you use?

[2000GotBoxS]

The disintegration of foam in the HVAC is pretty normal for a 15 year old car. I would not worry about that being the cause unless the noise goes away when you turn the AC and the inside fan "oFF".

 

What diagnostic tool did you use?

Hey Loren,

 

The noise does go away when I turn the AC off.  In fact, that is what I am doing in the video when the noise stops for the few seconds.   I reached in and turned the fan all the way off, thus turning the AC off.  Then, I turn it back on, and you can hear that sucking sound, then the hummm again.  

 

However, I have also heard it when the AC is off, and none of the interior HVAC system fans are running.

 

I have a Durametric tool for Porsche.  The only codes I have are alarm and air bag codes that I am still sorting out.  Nothing in the HVAC system or in the fuel system.

 

B

[Loren]

I suspect then that foam has hung up a flap (or two) may have even damaged the blower fan (for the interior).

Do a search here as several have had similar problems - a bit of work to correct the issues but likely good for another 15 years after that.

[RFM]

The sound can be caused by the A/C, the pipes run along the right side of the car, inside the wheelwell and next to the cabin air filter. Is there ever maintenance done at the A/C such as refreshing the refrigerant and replacement of the drier/filter, it should also be done to a 15 year old system.

[2000GotBoxS]

Sorry guys, I have been busy, haven't had a chance to tackle this yet, but, I soon will, and I will keep you posted.

 

B