A/C still isn't cold enough, no leaks, charged correctly
Also, switching to different fan positions doesn't always work. Like when I set the lower vents only, air is still coming from the front vents. Or when it's set to windshield and lower, its coming from all 3. Very annoying, I think it's an MB quirk though. Makes me really miss my e30 and it's sliding vent adjusters
I've noticed other cars/trucks I drive leave puddles of water when the A/C is on but I rarely see any with the e55, could that mean anything?
Might help narrow down the source of the issue.
Can anyone confirm that their AC does actually blow super cold like other cars or it is some kind of MB safety bull? My AC is never off in any car I'm driving. So far the w210 has been the weakest while holding the most freon lol.
Last edited by THEhomelessONE; May 19, 2015 at 03:02 PM.
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I've let my car idle with the AC on for a few minutes as well as after I've been driving with the AC on for over an hour, and there's never any water under the car. My evap sensor is reading 44f and I believe the compressor shuts off around 36-38f. Could anyone post a pic of where the evap drains are inside the car or how to access them? Going to stop by the shop tomorrow and try cleaning them out with compressed air.
The AC is weak even on the highway but my aux fans never come on around town either. They do turn on if I do that AC test. Is there a temp switch for it or is it reading off the engine coolant temp sensor? Is there only one coolant temp sensor? Read it can cause the AC to disengage as well as pull timing to save the motor. The car mostly feels "okay" but once in a while it feels like it has another 20-30hp.
Here's my readings:
1-66
2-123
3-80
4-80
5-42
6-179
7-13
8-120
Is there a switch or temp sensor that controls the AUX fans, and is there an easy way of cleaning the drain lines from inside the cabin? Couldn't get to them underneath the car.
New readings:
1-64
2-145
3-73
4-76
5-42
6-193
7-15
8-136
Shouldn't my freon temp (8) be much higher? Everything else looks good to me so I'm really lost here.
These are all signs of a failing compressor right? Don't think its the expansion valve since it changes directly with rpm. What should my heater core temps be at? Noticed they were much cooler on the highway versus idling. Here are my highway readings.
1-71
2-75
3-46
4-44
5-49
6-173
7-7
8-75
Get the pressure readings. This will identify the pump as a culprit or not.
I would temporarily block the coolant inlet hose to the heater core and see if that fixes it. That will eliminate the duo-valve as a culprit
It is possible your evaporator/expansion valve has failed.
An AC system is very simple. The compressor pumps up freon, as a liquid, to the back of the expansion valve located in the evaporator. It's just like taking a can of air (that stuff you blow out computers with, etc) turning it upside down and releasing the pressure. The can get very cold. Just put metallic fins on the can and you have an evaporator core. The pump simply keeps a steady, circulating flow of pressured propellant "in the can". If the nozzle on the can is clogged or blown out, you won't get an optimal cooling effect. By the same token, if the metallic fins you put on your can of air are clogged with lint, etc and the coldness can not be removed effectively by air flowing over the fins, the can freezes up and doesn't work properly. The rest of an AC system is simply to collect the spent (sprayed) freon and make it recompressible back to a liquid by the compressor. (this is the condenser)
Also remember that you should always change the accumulator as well.
I get about 3 degrees cooler temps when I charged to 2.26lbs versus 2.2lbs. Not sure why this is, maybe the machine isn't measuring freon correctly. The label says 2.2lbs +0.07LBS. The left and right heater core temps drop to the high 30's. High side pressure around 15 bar.
The evap temp stays around 35-37f on the first 3 fan settings. On max fan speeds it fluctuates between 40-44f. His car stays ice cold on even the highest fan setting.
I changed everything I could think of, ended up replacing the condenser as well. Guessing it's either just how the car was made, or there is a sensor giving a bad reading. I read these compressors can adjust how much they pump, what sensor sends the signal to the compressor? Could the climate control be giving a bad signal even though the temp is set to LO?
Running out of ideas, having a hard time believing an MB can't match the A/C of a smaller capacity BMW 5 series of the same year.
How would I go about testing the unit?
Last edited by THEhomelessONE; Jul 31, 2015 at 05:30 PM.
I have noticed that when I stop in traffic, the evap temps go up. I have a suspicion that the condensor is not getting enough airflow. I think spraying it with water to cool it down would be a good experiment. I do have the Star diagnostic system, and I have a feeling that the compressor is not being commanded to maximum displacement when needed.
I would really like to know which wire to tap into and monitor that actuates the compressor.







