Whistling sound from interior A/C
Thread Starter
Junior Member
Joined: Mar 2012
Posts: 41
Likes: 0
2001 E320
Whistling sound from interior A/C
Starting to warm up in Southern California so turned the A/C on. Air cold. Fan speeds work but slight whistling sound from right side of dash. Sounds like wind noise but still happens when car is stopped. Doesn't seem to get louder by increasing fan speed. Anyone know what could be causing this?
Super Member
Joined: Jan 2010
Posts: 563
Likes: 31
From: The Villages, Florida
2006 E320 CDI
I know that this is a dumb suggestion, but are ALL the air vents open? In my e320, sometimes my wife will shut off her window vent, and at times the system will whistle.
Mike T.
Mike T.
Member
Joined: Dec 2011
Posts: 167
Likes: 0
From: San Antonio, TX
Like The Stig
You are low on R-134A refrigerant. Go buy a can at autozone and check to see if that solves the problem. My ac started whistling as well, i filled her up and the whistling stopped, it was more of a hissing sound though.
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Thread Starter
Junior Member
Joined: Mar 2012
Posts: 41
Likes: 0
2001 E320
Still can't find the cause of the intermittent whistle. Ran tests again. Found one fault Eb1. 234. Which I understand is the sun sensor. Turned on air with windshield covered which probably triggered the fault. Cleared it and will re check. Here is latest A/C values.
1 80
2 94
3 40
4 40
5 32
6 184
7 15
8 120
1 80
2 94
3 40
4 40
5 32
6 184
7 15
8 120
Member
Joined: Dec 2011
Posts: 109
Likes: 0
From: Toronto
CL55, S550, 450SL
Make sure the cabin air filters are installed properly and are clean. I had a whistling as well on my old W220 so I replaced the filters in the glove box and the whistling went away. It's worth a shot!!
Thread Starter
Junior Member
Joined: Mar 2012
Posts: 41
Likes: 0
2001 E320
First thing I tried. It helped the airflow because the old ones were dirty. I think a tiny twig or leaf is keeping one of the dampers from positioning properly. I hope it is not the passenger side fan. If so, I will fix when it gets worse. Until then the A/C is blowing cold. It is a minor irritation fixed by playing the radio louder. Thank you all for trying to help.
