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Any ideas what this is?

S

sp1ke

Spa-Francorchamps
Joined
7 May 2009
Messages
345
I finished tinkering with the car this afternoon, then started the car to check all was well. A minute or so after firing her up, there was a loud noise & vibration coming from the passenger side dash area & some tiny pieces of foam fragments blown out of the upper dash vents.
The ac was still blowing cold, & everything appeared to work aside from the horrendous racket which would rise & fall when adjusting the AC fan speed & vanish with the fan turned off.

After my initial panic subsided, I eventually deduced there must be some debris in the heater/ac blower motor.

I followed the steps from https://www.pelicanparts.com/techar...a/103-ELEC-HVAC_Motor/103-ELEC-HVAC_Motor.htm to remove the blower motor, & found a thin membrane floating around in there.See attached pic of the removed item.

After removing the membrane & re-fitting the blower, the noise has thankfully gone. However this leaves me wondering what this item is & how to replace it.

I'm guessing it's some kind of vapour barrier that belongs somewhere in the AC ducting, but not sure where.

Any one have any ideas where it came from & what the part number might be?
 

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I have to admit this is a new one on me .. that part is the foam cover that sits over the pollen filter .. its job is to stop water ingress to the pollen filter and so the car .

i would guess at rodent damage as i see no way it can just come loose .. but from the picts and no chewed edges i doubt that ...

I'm kinda stumped as to how it came loose to be honest .
 
Many thanks Ian

I've not removed the filter, but at 1st sight there is no obvious sign of rodents & the filter looks intact.
The membrane measures approx 10x15cm so it seems a little small to serve any useful purpose above the cabin filter. Does it belong below the cabin filter?
 
Sorry .. yes .. :oops:

If you remove the filter you should be able to see or put your hand in and feel a plastic panel , this has that foam on it ..

Its the air recirc flap .. it closes off the outside air basically .

It will still do its job as it's never a total seal .

I've never replaced one but im guessing its dashboard out , heater box out then a strip and replace .

I tried to get a photo of this on a 997 today but i just ended up with black pictures that didn't really show anything so the description is the best i can do .
 
Thanks again Ian

I've attached a pic of the flap beneath the pollen filter. The rubber gasket below the pollen filter housing & the inner foam ring above the flap seem fine.

It's not shown in the pic, but the left side of the spindle for the flap sits in a groove, so it appears it may be possible to slide up the left side, & then remove the flap after the pollen filter housing has been removed.

I've had a look on PET, but can't see any sign of the flap, or any kind of foam membrane around there. So perhaps it's only available with the whole blower motor housing.

Do you think it's worth pursuing a replacement, or leave it be?
 

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I think the flap sits inside the red piece in the pic above.
The only item there which looks remotely like the rogue foam piece is the green item in the pic above. It's not clear where that fits though.
 
i would imagine its part of the heater assembly .. it's certainly not listed on the parts images you have posted .

This sort of flap usually is held in place by 2 halves of a casing and as such needs it to be split apart to replace .

997 and they are on both sides of this flap .. your image shows the recirc flap closed .. i feel it's on the underside so open the flap and have a look .

Basically there is no where else this could have come from and its the correct size for this flap .. it's also identical to a 997 .. as i had a look yesterday and it's the same material .

I'm not a driver .. just a humble mechanic so i'm not sure how often people actually switch it to inside air only .. at a guess not often so i would say just leave it ..

The cost implications would imho outway the benefits .

Im also unsure how it could come loose though hence my rodents comment .. its all i could think of basically :)

No 5 looks like the foam panel the heater pipes go through .. directly behind the battery

red item is indeed where this flap lives .
 
I thought I'd wrap this thread up with some pic's for anyone who has the same issue in the future & stumbles across this.

Pic below shows the lower side of this flap. If it did previously have a foam membrane layer, then there is no evidence of it or any residual glue.

The red arrow in the 2nd pic shows what looks like the same type of membrane lining the inner wall of the chamber. I'm presuming it has a foam backing, based on the debris I found. It appears to be some sort of insulating layer inside the blower motor housing, which only seems to be available to purchase with the whole housing.

The flap still functions, as does the a/c & heating, so there appears to be no noticeable loss of HVAC performance if some of these foam membrane thingies are displaced. So I'll go with Ian's advice & ignore it.

There is no sign of rodents, so I'd guess a combination of age & hot weather may have been factors.

I also found https://www.youtube.com/watch?v=Ok4dBOcYTHw
The symptoms sound similar if not the same, & the last comment from Brandon Bentley mentions
"I called a Porsche dealer, they said it is the lining not the seals of the blower box/assembly and to not worry about it other then some bits could stop one of the doors from closing when you choose up/down/forward settings. I mentioned the moisture thing and they said it's actually the insulation on the inner walls of the heater box..."

Thanks again for sharing your insights Ian, as always very much appreciated :thumbs:
 

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