Air conditioner tip/check
Thread Starter
MBWorld Fanatic!
Joined: Jul 2006
Posts: 1,779
Likes: 11
From: Long Island, NY
2004 E320
Air conditioner tip/check
MY 2004 manual states that air recirculation is activated when the A/C is turned on.
I've never found the A/C particularly cold in my car and the other day noticed (yea, I never looked before) that the light was OFF (little car outline w/the loop arrow).
So, obviously outside air was coming in.
Turned the sw ON and low and behold, nice COLD air. In fact I also tried turning the sw on w/the A/C off.
Guess what, turning the A/C on deactivated the sw.
I don't know if this is peculiar to my car or year but the point of this post is that you should check that when you turn on the A/C, check that the recirculation light is on.
I've never found the A/C particularly cold in my car and the other day noticed (yea, I never looked before) that the light was OFF (little car outline w/the loop arrow).
So, obviously outside air was coming in.
Turned the sw ON and low and behold, nice COLD air. In fact I also tried turning the sw on w/the A/C off.
Guess what, turning the A/C on deactivated the sw.
I don't know if this is peculiar to my car or year but the point of this post is that you should check that when you turn on the A/C, check that the recirculation light is on.
Senior Member
Joined: Sep 2006
Posts: 413
Likes: 3
2003 E320
I live in Atlanta and I would venture to guess that our black 320 gets hotter than any color car in NY. I know you have some hot days but our humidity is fierce and I have been told that diminishes the AC performance as well.
If you are not getting comfortable with outside air, you may have a low 134 charge. I have other vehicles that do about as well but I will say that when the auto button is on and those fans go into giddy up mode, at least I feel that relief is on the way. They are so loud, people actually stare at the hood as if they expect the thing to fly. I have no complaints about cold air.
If you are not getting comfortable with outside air, you may have a low 134 charge. I have other vehicles that do about as well but I will say that when the auto button is on and those fans go into giddy up mode, at least I feel that relief is on the way. They are so loud, people actually stare at the hood as if they expect the thing to fly. I have no complaints about cold air.
MBWorld Fanatic!
Joined: Mar 2004
Posts: 5,017
Likes: 16
From: Ft. Lauderdale Area, USA
2015 ML 350
MY 2004 manual states that air recirculation is activated when the A/C is turned on.
I've never found the A/C particularly cold in my car and the other day noticed (yea, I never looked before) that the light was OFF (little car outline w/the loop arrow).
So, obviously outside air was coming in.
Turned the sw ON and low and behold, nice COLD air. In fact I also tried turning the sw on w/the A/C off.
Guess what, turning the A/C on deactivated the sw.
I don't know if this is peculiar to my car or year but the point of this post is that you should check that when you turn on the A/C, check that the recirculation light is on.
I've never found the A/C particularly cold in my car and the other day noticed (yea, I never looked before) that the light was OFF (little car outline w/the loop arrow).
So, obviously outside air was coming in.
Turned the sw ON and low and behold, nice COLD air. In fact I also tried turning the sw on w/the A/C off.
Guess what, turning the A/C on deactivated the sw.
I don't know if this is peculiar to my car or year but the point of this post is that you should check that when you turn on the A/C, check that the recirculation light is on.
Last edited by Barry45RPM; Jul 8, 2009 at 10:48 PM.
Senior Member
Joined: Oct 2006
Posts: 470
Likes: 3
From: McLean, VA
2003 E500 Benz & 2015 BMW M235ix
MY 2004 manual states that air recirculation is activated when the A/C is turned on.
I've never found the A/C particularly cold in my car and the other day noticed (yea, I never looked before) that the light was OFF (little car outline w/the loop arrow).
So, obviously outside air was coming in.
Turned the sw ON and low and behold, nice COLD air. In fact I also tried turning the sw on w/the A/C off.
Guess what, turning the A/C on deactivated the sw.
I don't know if this is peculiar to my car or year but the point of this post is that you should check that when you turn on the A/C, check that the recirculation light is on.
I've never found the A/C particularly cold in my car and the other day noticed (yea, I never looked before) that the light was OFF (little car outline w/the loop arrow).
So, obviously outside air was coming in.
Turned the sw ON and low and behold, nice COLD air. In fact I also tried turning the sw on w/the A/C off.
Guess what, turning the A/C on deactivated the sw.
I don't know if this is peculiar to my car or year but the point of this post is that you should check that when you turn on the A/C, check that the recirculation light is on.
Thread Starter
MBWorld Fanatic!
Joined: Jul 2006
Posts: 1,779
Likes: 11
From: Long Island, NY
2004 E320
@Clinton/Barry...yes, refrigerant level is OK. Barry,If both your cars did/do the same thing, then it must be a printing error.
BTW Clinton, I know your weather well. I spent 53 weeks in Valdosta, GA, back in '65. You're right, it can be brutal in the summer.
Member
Joined: Dec 2007
Posts: 125
Likes: 1
From: Orange County, CA
2004 MB E-500 & 2000 Honda Accord Coupe
How would you know if your refrigerant level is low? On the AC panel you can check the refrigerant pressure and mine show I have 10. My AC is not that cold compare to my other car.
Recirculation button is OFF by default on the 04. It closes when the outside temperature is above 74deg but the light doesn't lit on.
Recirculation button is OFF by default on the 04. It closes when the outside temperature is above 74deg but the light doesn't lit on.
Senior Member
Joined: Sep 2006
Posts: 413
Likes: 3
2003 E320
A "rule of thumb" for 134 and r-22 (home) is 18 to 21 degrees temp drop from cabin (room) temp to discharge air. IE if the cabin temp is 80 the discharge should be AROUND 60 degrees. All of the mechanical engineers can start flaming now. This does not account for relative humidity, dry bulb temp etc. but it is a reasonable guide. If you are pulling in 90 degree outside air by using the fresh air intake, you need to subtract from that temp. so your discharge will be 70 degrees. This works down to the limit on A-C which I think is about 54-55 degrees. Obviously if you start a black car in the sun on a 95 degree day and let it idle, your readings will be less than stellar. You can buy a vacuum gauge that fits on the SUCTION hose Schrader valve and get an idea if it is within the acceptable range. They come in a variety of flavors and start about 15 bucks. IF you are going to brave charging the system, you can damage lots of stuff by OVERCHARGING. If you don't get enough gas in the system it simply does not cool effectively. I have never added compressor oil but that is another area best left to knowledgeable people. Unless you have a leak, my experience has been about 10 years before enough gas escapes to cause any noticeable difference.
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MBWorld Fanatic!
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From: NM
2023 AMG EQS
similar to the airliners with all the passengers' breathing the contaiminated air from each other! In fact, sometimes when I fly on an airplane on a five plus hour tirep I get a cold afterwards from the sick air.......flew back from 7.5 hour Paris flight last May and then got a bad cold.
When I read the manual it said recirculation is always off unless you select it or press MAX. The reason is so that you windows don’t fog up. Even when you press max, the car will only recycle air for a limited time, I think 5 mins. However I have found that if you are in a very hot environment 90f+ then the windows will never fog with recyled air. You can also apply never fog to you windows.
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Joined: Sep 2005
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From: Albuquerque
'10 CL550, '12 GL550
Here's the REST of what the manual says:
You'll note that "high" is not defined.
Note also that this apparently only occurs when a/c is turned on before starting car.
Nevertheless, air should be cool and pressing the button not required.
It's my experience that the ONLY advantage to switching the system away from AUTO is to enable manual control of fan speed. I remain unconvinced that temp setting has any effect except in AUTO mode.
The air recirculation mode is activated
automatically at high outside temperatures.
The indicator lamp on button, is
not lit when the air recirculation mode
is automatically switched on.
A quantity of outside air is added after
approximately 30 minutes.
If you have turned off the air conditioning
or the outside temperature is below 41°F (5°C), the
air recirculation mode will not switch on automatically.
automatically at high outside temperatures.
The indicator lamp on button, is
not lit when the air recirculation mode
is automatically switched on.
A quantity of outside air is added after
approximately 30 minutes.
If you have turned off the air conditioning
or the outside temperature is below 41°F (5°C), the
air recirculation mode will not switch on automatically.
Note also that this apparently only occurs when a/c is turned on before starting car.
Nevertheless, air should be cool and pressing the button not required.
It's my experience that the ONLY advantage to switching the system away from AUTO is to enable manual control of fan speed. I remain unconvinced that temp setting has any effect except in AUTO mode.
Last edited by lkchris; Aug 31, 2009 at 04:45 PM.
