A/C blows hot air first few minutes then turns to slightly cool air - Benzworld.org

Guest (MBNZ) · 07-23-2002, 10:05 PM

When I start the car and turn on the A/C, I get a blast of hot air for about 10 minutes then air starts to cool slighly but not cold air, even control set to min. 
 
I just had freon added 6 months ago. I noticed when the A/c fan in front of radiator is turning, the air is cool but when it stops the air started to warm up. 
 
Anybody have any idea why this happens??

Guest (MBNZ) · 07-24-2002, 04:08 AM

Rob, did it do this when they first recharged the system 6 months ago? Did they check for leaks? When you say the fan... is that the one that comes on when the motor is at a high temp?? (year/model??) Well, can you see the clutch pop out on the compressor while it's running?

Guest (MBNZ) · 07-24-2002, 06:55 AM

The car is 1986 560SEL 
 
They did not check for leaks but they could only add less than a can of freon. They found the reason it was not cooling was not the freon but the a/c fan not kicking in. They replaced a little part (white ceramic--relay or resistor) that starts the fan. That was 6 months ago. 
 
Since then it was working until a week ago when the water pump and thermostat was replaced. 
 
Yes, I am talking about the a/c fan in front of radiator that kicks in when temp is hot. It kicks in but stops turning too soon. 
 
No, I have not check the compressor. I will have someone take a look at it. 
 
Thanks.

Guest (MBNZ) · 07-25-2002, 06:25 AM

Wow, my fans in front never kick on. I guess my car never gets hot enough. (whew...) Anyways...you can look to see if the clutch is popin' out yourself. Just turn the a/c on and if ya listen good, you can even hear it (with your windows down) :) assuming door insulation is still good :) You can raise the hood and look at the front of the compressor and it should pop out and after a while it'll turn off and you should see the clutch go in/stop turnin'. I also heard someone say that a drier replacement helps. ??? Good luck. I'm still trying to get mine ice cold too.

Guest (MBNZ) · 07-25-2002, 02:25 PM

Hi ! 
I belive that the Mercedes AC generally is a little slow, when I start my 560 SEL-86 is begins with a hot breeze. IÂ´ve filled it up for one month ago, and it still starts with warm air, but it responds quicker now. after the fill-up. 
 
Regards 
Mats 
Sweden

ashmead · 08-12-2002, 06:38 PM

When you first turn on the AC and the fan is on auto, the fan speed should be low until cool air is available. Then the fan should kick up to a higher speed. When the desired temp is reached, it will drop back down.

To check your monovalve and heater function, select econo mode (2d button from right). In that position the AC is off and unheated outside air should come through the center vents. If you get heated air instead, your monovalve is bad, causing the heater to fight with your AC. Replace the monovalve insert ($30).

Eric · 08-15-2002, 05:22 AM

I was checking everything with my AC again and I was bout' to charge it with some freon. Then I noticed my fan in the front wasn't workin'. I changed the fuse, added just one can of freon and man... It's nice and cold. I was just thinking of changing over to the new stuff r134a(something like that), but now... I'll wait a lil longer. :D Good luck to yall.

Quote:

When you first turn on the AC and the fan is on auto, the fan speed should be low until cool air is available. Then the fan should kick up to a higher speed. When the desired temp is reached, it will drop back down.

To check your monovalve and heater function, select econo mode (2d button from right). In that position the AC is off and unheated outside air should come through the center vents. If you get heated air instead, your monovalve is bad, causing the heater to fight with your AC. Replace the monovalve insert ($30).

Keith Lucy · 08-18-2002, 04:07 PM

How do you check if the Aux fan is working? When should it be on?

Eric · 08-20-2002, 06:27 AM

Well, I thought it only came on when the engine is really hot, but seems like it's on whenever I put the a/c on. Well, I haven't really look at it to see if it's on the whole time the a/c is on, but when I was checkin' it out... and found that bad fuse, changed it and it stayed on. I didn't get in and turn off the a/c to see if it would turn off. I just got in and noticed the quick change of coolness :) Heck, I told my friend to shut my hood and I hit the street to really feel it cool off. :) good luck