I've recently brought my CLS55 in to the dealer to have the AC checked. They recharged the system, added a small amount of freon and told me everything was running exactly how it should. The problem is, I feel the AC is horrible. Granted, I live in south Florida but this AC is by far the worst I have ever had in ANY car. It's been like this for a few years but now that my car is out of warranty I am considering using one of those additives.

It literally will take 3-5 minutes on full blast set to LO temp for the car to be even tolerable.

 

I remember seeing something where it can be programmed to get colder quicker in hot climates. Contact Mackhack on here, he might be able to help you.

 

have you tried running the heater on full blast for a few minutes
i had the same problem but read here that trick may work. My AC improved in my C32.

 

That's normal for these cars in hot weather. Mine sucks too! MB is not well known for cold AC. The best thing I can do is use summer opening feature to let the hot air escape. Then set to "low" and auto mode, with recirc on. You should see "max cool" in the display if it's coded correctly. This allows max compressor and faster engine fan speed. Germans have always been more worried about heat than AC! Are your windows tinted? Do you have a folding sunshade to cover your front window? MB sells a reflective folding shade that fits good. Do you keep your sunroof shade closed? Every little bit helps.

 

Thanks for the ideas. My windows are limo tinted and I use my rear sunshade but I don't use a front sun screen yet. I'll pick one up this weekend. I've also started to use the remote to open the windows. It seems like my car blows hot air for the first couple minutes, then it slowly becomes cool but never truly cold.

I'll try out the heater thing next time I drive.

 

Next time pop your hood and feel the low side ac hose that sits on the drivers side wheel arch. That hose.should start to cool almost immediately. If it takes over a minute then you have a problem...typically the compressor is on its way out. I just fixed an E320 with this issue. Took 3 tries because we didnt understand the customers complaint.Typically the car will have to sit overnight over

 

Sry posting from phone, impossible

 

I have a theory about condensation and freezing in the excessively humid areas like the Gulf coast. I was there last year and while driving down the highway, my ***** would get w-e-a-k! I'd turn off the a/c for about 15 minutes and turn it back on and it would work, as if something had melted away.

I've heard of the a/c being able to be altered in STAR, but I don't know where. I would like to do this as I am moving to AZ next year.

That being said, the a/c along with the factory audio are the two most underwhelming things on this car. I had a Lexus LS 430 that was amazing in both of those aspects. I know, different class of car, but still, this is a $90-100k car.

 

It's ice cold within 15-20 seconds. I'm pretty sure the 90-100 degree heat is the culprit. I'll just get in the habit or using a sunshade when I can't park in a garage.

 

My wife's IS350 has an amazing audio/navigation system and her a/c blows ice cold from the second the car turns on. Yet, her car was not even half the cost of my AMG. Different priorities I guess.

 

Both of mine do the same thing. I think the evaporator is freezing over

 

Why did the dealer "recharge and add a small amount of freon" (freon is R12)
I am sure you mean R134a, anyway you can not just add R134a in our variable displacement compressors. The amount of charge can only be measured (outside) before it is introduced in to the system. If the system is not charged to exact spec it won't work very well.

What you need to do is post up the diagnostic values 1-7 and that will indicate what kind of problem you may have.

FWIW my drivers side vent discharges 38* air a few minutes after start with 115* interior temp.
Setting the temp to LO makes no difference in how cold the discharge air temp is during initial cool down, the control automatically dose this until the cabin temperature set point is reached.

 

Hey,
Long time no talk. I met you at Elliott's dyno day. My tech said he charged the system or something like that. I know of the diagnostic values that you are talking about but I can't figure out how to get them on my CLS. The directions that I have for the E55 seem to be missing a step or the buttons are different. Could you PM me if you are aware of how to run that diagnostic?

Thanks...

 

I've experienced this on a couple of different MB cars. The AC cools down quickly when backing out of the garage in the AM. A little slow after sitting in the sun at the office all day. Really slow if parked at the airport for several days.

I think it is inherent in the way MB designs their heating & cooling. In an MB the air always flows over the ac evaporator and then the heater core. If the car has been sitting in the sun long enough and the interior is 140 degrees, the coolant in the heater core is also 140 degrees. The AC system has to cool down the heater core before you start feeling cold air.

Most cars use a door to direct airflow around the heater core for ac, and through it for heating. A system that works like this doesn't have that "thermal inertia", if you will, of having to cool down the heater core before you feel cold air.

My $.01.

 

Try this, and guys this is not a bad thing to print and put in the glove box.

https://mbworld.org/forums/4876298-post202.html

 

Go to:

Control Units->AAC-Air-Conditioning->Control Unit Adaptations->Read Coding->workshop coding (or Alle Codierung)

You will see Hot countries setting and set to YES

You could also play with the Increase blower stages but that only works for ASIA mode not ROW.

Though, I am not sure this will help a whole bunch. My AC sometimes is not that cold but then again I have not topped it up for some time.

 

Thank you!

 

Actually, this part sounds like a bad A/C compressor. I have had a similar experience but on another car. Exact same symptoms. Tried topping up, evacuating and refilling, no leaks ... it would work for a while, then the compressor would turn off. If I left it off for 15-20 minutes and turned on, it would be cold again then the cycle would repeat. Switched the compressor and it was icy cold again.

 

Just another tidbit to add to the discussion, but an a/c will blow it's coldest air at a LOW fan speed setting. At a HI speed, the air is moving too quickly across the evaporator to chill it down to it's lowest possible temp.

 

i had the same problem but read here that trick may work.

 

Sounds like ice was forming on the evaporator, which blocks the airflow. You can hear the fan spinning, but get no air out the vents and hence no cooling. Turning off the ac allows the ice to melt, and then it works normal again for a while.

Buncha different things can cause this. It indicates a problem of one kind or another.