Mystery AC part (applies to E3 and E9)

Dick Steinkamp

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There is a hunk of some sort of insulation glued to the inner "roof" of the AC intermediate piece...

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I've removed it since it is coming apart.

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It is not shown separately from the intermediate piece in RealOEM. Maybe in the parts book?

Does anybody know what its purpose is and what material(s) would make a good substitute?
 

bluecoupe30!

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Hi Dick, I recently had my heater out for a rebuild and encountered this same situation with the duct. Not an a/c car, but the duct is very similar. The fabric had completely collapsed and impeded any air movement. Took it out and it was all intact. Threw it in the washing machine, hung it to dry, sewed up the edges better, re-glued, added new felt at the sides, good as new. The fabric is like a velour or felt type cloth. Can only guess as to its function. Perhaps to prevent whistling or similar noise when fan is on full? Anyone?
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Dick Steinkamp

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Thanks, Mike.

I don't have much hope of mine coming through a machine wash cycle intact. I'll try hand washing it. It's pretty much in one piece. Some repairs needed, but if it will wash, I think I can glue it back in pretty much as is.

I sure would like to know why it is there.
 

Boonies

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No idea why it is there, but also found the red fabric on my e9 when I had the heater and AC apart for service prior to renewing the upholstery (still underway). Mine was also in good shape, and I did a minor cleaning and re-gluing. Assume it is noise control.
 

bluecoupe30!

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Thanks, Mike.

I don't have much hope of mine coming through a machine wash cycle intact. I'll try hand washing it. It's pretty much in one piece. Some repairs needed, but if it will wash, I think I can glue it back in pretty much as is.

I sure would like to know why it is there.
Well yeah, the whole point in trying to wash/salvage this piece is to avoid trying to source a replacement fabric-like-the-original-that-Fritz-used-back in ' 72! Got lucky!
 

thehackmechanic

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If it covers the entire cold air outlet from the evaporator, its function may have been to eliminate "spitting" of condensed water off the evaporator core.
 

Dick Steinkamp

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I hand washed mine in a bucket with some detergent.

#1 the water in the bucket turned to black mud. Whatever it is, it was filthy.

#2 Not much of it remained after washing. :(

I am tempted to not try to duplicate it but rather to reassemble without it. It seems like a great source of mold and mildew. Has anyone removed this part? If so, what changed if you did? Was the system noisier?
 

billpatterson

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Happy NY

Honestly...I do not remember that piece of material, when I took my heater box apart. If it was in the interior of the heater/AC box, I think it is a form of sound insulation though.

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eriknetherlands

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The textiel +foam part was Standard on our cars, seems to be in both e3 and e9.
See my DIY thread here, with some pictures.

Thread 'DIY - Heater unit rebuild' https://e9coupe.com/forum/threads/diy-heater-unit-rebuild.38896/
I've glued it back.

With regard to the purpose: in modern HVAC systems this is never seen, probably for good reasons.

My thoughts:
The textile:
- reduces the airflow,
- reduces some noise,
- is just another failure mode waiting to happen if the glue lets loose.

I've glued it back as I am strving for 99% originality. If you aren't into originality I'd leave it out.
 

Dick Steinkamp

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Thanks, Erik,

I'm going to take your advice. There wasn't much left off mine anyway. It was more of a "science project" than anything else with the quantity of mold, mildew, dirt and other filth. I'll report back with any change in noise, etc. when I have the AC back together and working.
 
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