THEhomelessONE

Held vacuum fine, charged back to 2.2lbs or whatever it is but my beater camry has colder A/C. Is there any components I need to replace? Drier, evaporator? Not too familiar with A/C systems. Don't think it's the duovalves sticking either as the A/C is weak even before the car is fully warmed up. Feels like the air is still too humid. New cabin and charcoal filters.

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

NAFT1

Could be the restrictor/evaporator valve or the drier. Small pieces of metal or crystalized lubricant can clog the drier over the years. A complete flush and replacement of it might work. Another problem might be growth in the condenser where humidity is removed from the outside air, but if that were the case you'd probably have low airflow and a musty smell.

THEhomelessONE

I'll change those parts out soon, it did perform better after the flush for about a month but not how a car with 2.2lbs of freon should. I do have a humid/musty smell, would the growth be between the condenser and radiator or inside the condenser? Made sure all drains were free of debris as well.

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?

illest

Try this http://www.eclassbenz.com/2010/02/ho...-malfunctions/

Might help narrow down the source of the issue.

CharlyE500

Same thing happened to me... I end up changing the AC compressor for $400

THEhomelessONE

I'll post up results from the A/C test today, thanks for the link. Lol I hope it's not the compressor, I'll change the cheaper stuff first. I think my evap drain lines might be clogged too. Any recommendations on how to clean these out? I have access to a shop/lift.

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.

CharlyE500

My car is damn cold now after replacing the compressor and refill freon.

illest

yup mine is very cold as well.

THEhomelessONE

Did another flush last week just to be sure and no freon leaked. Held vacuum great. Two stored error codes, b1416 for coolant circulation pump and b1231 for ECT sensor. Erased codes but circulation pump code came back. Does this pump work when the car is shut off to cool down the engine or just to keep the cabin warm?

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

THEhomelessONE

Had the car in the shop today, let it idle with AC at full blast and water was coming out of the drains but about half of what a normal car would. My AUX fans never kicked on even with engine temps almost hitting 90c. The fans do come on if I hold both AUTO buttons for 10 seconds.

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.

SICAMG

First of all get some pressure readings. Your low and high side will tell you whats going on "IN" the system. Lets assume its 70* outside....we need around 30-35psi on the low side and 150-175 on the high side. Then go from there.

THEhomelessONE

Thanks, I plan on checking the pressures over the weekend. I tried the pressure test on the highway today after about 15 mins of driving and my high side pressure hovers around 6 or 7 bar. At a stop it will climb up to 10 bar and if I leave it long enough at idle it'll get up to 15 bar.

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

SICAMG

I am a little confused with your numbers. Do you have a manifold gauge set that you can hook up to your car? When you get your readings I can go from there. When I teach a class this is the ONLY way to properly do it.....you have to have a reading from the system with the gauges. Let me know.

THEhomelessONE

I do at the shop, will be there Friday or Saturday, I'll make sure to post numbers. Thanks for your help!!

Schweinhund

The aux fans will come on when they are needed. The mechanical fan is quite effective and runs all the time (more or less)

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)

SICAMG

Interesting .....Homeless just the pressures please. I have this going to my email so I will know when you post.

THEhomelessONE

So my low side pressures were between 70-90psi and high side was around 100-120 psi. Vacuumed out 2.2lbs. I ordered the updated Denso compressor, Behr drier, ND8 oil, a Rein? expansion valve, and if the condenser isn't too expensive I'll get that too. Cost me less than $300 for parts except condenser so figured might as well replace as much as I can. Hopefully I can get it done today after trans flush.

SICAMG

Sounds like the compressor for sure. But....what does the decal say for how much should be in the system. You say you took out 2.2 lbs. Just curious.
Also remember that you should always change the accumulator as well.

THEhomelessONE

Decal says 2.2lbs. I'm using a Robinair machine that I'm not familiar with. I'm assuming you know how to work these AC machines as you teach AC classes? When I pull a vacuum, does that also pull all the oil out of the system? I bought 250cc of ND8 oil and I plan on injecting 90cc, already put 30cc in the compressor, 15cc in feed and 15cc in return. I'm replacing the condenser, compressor, expansion valve, and drier/accumulator.

THEhomelessONE

Got it figured out. I'm not sure what was wrong but it's working great now. Evap temp sensor goes down to 37f while outside temp is 58f and freon temp is around 125f. Can't wait to test it out on some 100 degree days. Thanks for all the help guys.

SICAMG

Glad you got it sorted out!!

THEhomelessONE

Just a little update now that it's seen some 100f+ days. I had to charge up to 2.26lbs to get a bit cooler air. It gets cold but can't touch my cousins E39 BMW. His car also holds almost or about 2lbs of freon, but less than mine.

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.

illest

A few years back I had my car in the shop because the A/C was not getting cold and they replaced the Climate control unit in the dash because it was sending weird signals and so the compressor was not kicking in when it needed to.

THEhomelessONE

My uncle also recommended looking into a new climate control unit, but he works on Audi/VW, might be a common thing with MB. Did you use a new unit or one from a yard? Wondering how much a new one goes for, thanks for the help!!

How would I go about testing the unit?

michalk

I am currently troubleshooting the same problem. 2004 E55. The climate control parameters usually show around 15C on the evaporator core, but I know it can go lower. I've seen 2C in Monday in 98F weather. Sorry for mixing units.

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.