Bizarre A/C problem
05-20-2018, 03:16 PM
#1
Junior Member
Thread Starter
Bizarre A/C problem
05 E500 wagon . The last 3 days I have been experiencing a bizarre AC problem. After about 3 to 4 hours of driving Non-Stop the AC air flow nearly stops but I can feel that it is still Cooling and the blower motor gets noisy as if it's intake was blocked, this would be similar to putting your hand over vacuum cleaner when your vacuuming , no changing of any of the vent positions or recirculation has any effect but in the morning afterwards I'll go out to the car and everything works fine. I have checked all of the vent positions they work fine there is no clicking and there is no hissing from the AC system. I have read about 10 of the pages in the search regarding AC problems and I have not seen this problem yet.
05-20-2018, 08:37 PM
#2
Super Member
My take is you are low on Freon. When this happens the evaporator coil freezes (ices up) and you will have no air flow, after it melts, you have air flow. You may notice it more on humid days and longer drives over one hour.
Mike T.
Mike T.
05-20-2018, 09:02 PM
#3
Junior Member
Thread Starter
That actually describes the situation pretty accurately because we've had torrential downpours in the last 3 days so the humidity which is generally mild has been very high the last 3 days, thanks !
05-21-2018, 12:14 PM
#4
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1922 Ford Model T / no OBD
Those cars have anti-freezing sensor, that should prevent freezing.
That said, you have at least 8 sensors regulating AC work and crystal-balling the problem has low accuracy.
Find a way to read the sensors and you will need to read it once on cold morning before engine start, to check sensors accuracy and then at least one more time when you have hot cabin and AC at full blast.
That said, you have at least 8 sensors regulating AC work and crystal-balling the problem has low accuracy.
Find a way to read the sensors and you will need to read it once on cold morning before engine start, to check sensors accuracy and then at least one more time when you have hot cabin and AC at full blast.
05-23-2018, 02:02 PM
#6
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1922 Ford Model T / no OBD
Do you have REST button on your climatronic? Those allow displaying sensors values on LCD just like older cars did.
If not, you need more advanced scanner. Follow the guide at http://www.mercedesmedic.com/ac-air-...le-codes-list/
W211 has only OBD plug, so this is the way to connect.
If not, you need more advanced scanner. Follow the guide at http://www.mercedesmedic.com/ac-air-...le-codes-list/
W211 has only OBD plug, so this is the way to connect.
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05-23-2018, 04:30 PM
#8
MBWorld Fanatic!
IMO if it were low on freon it wouldn't take 3-4 hours of non stop driving to describe your issue. Kaj is correct, anti freezing is built into the evap housing and there's coding that specifically regulates such things from happening....
to me it sounds like you high psi line is collapsed. very common on w211 chasis. There is a liner inside the line that overtime gets lazy/collapses causing air flow restrictions.
besides all our speculations, best thing you can do is go to a shop and hook up gauges. Raw numbers will convey if there are any issues. who knows your compressor could be failing too.
to me it sounds like you high psi line is collapsed. very common on w211 chasis. There is a liner inside the line that overtime gets lazy/collapses causing air flow restrictions.
besides all our speculations, best thing you can do is go to a shop and hook up gauges. Raw numbers will convey if there are any issues. who knows your compressor could be failing too.
05-24-2018, 10:54 AM
#9
Junior Member
Thread Starter
I had a can of freon with a pressure gauge laying around , hooked it up , pressure was marginal at 25 psi , added can of freon , drove for 6 1/2 hours last night and problem did not reoccur but it was dry out with no rain still I think that the problem is resolved .
