Whistling sound from interior A/C
#1
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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?
#2
Out Of Control!!
To help eliminate any guess work, I would suggest that you go to the stickies and do the AC actual value test and fault test----then post the results. Good Luck!!
#3
Super Member
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.
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#10
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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.
#11
MBWorld Fanatic!
Yupp. Low on freon will make it sound like a whistling sound or cracking sound too as many described. Also, is the EC light on? If so you are very very low.
#12
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2001 E320
No lights no faults. Haven't had a chance to take cabin filters out and blow air through vents. If it doesn't rain this weekend, I will do it and report back.
#13
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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
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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!!
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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.
#16
Out Of Control!!
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----------outside air temp
3 40
4 40
5 32----evaporator sensor
6 184
7 15---refrig pressure
8 120---refrig temp
1 80
2 94----------outside air temp
3 40
4 40
5 32----evaporator sensor
6 184
7 15---refrig pressure
8 120---refrig temp
The other observations are in red---5 should be colder and with 7 at 15, 8 must be 144(law of physics on earth).
Still too early to pinpoint, however knowing the above I would put a set a gauges on the car and look at that data.