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W124-94 E320
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29 Posts
Discussion Starter · #1 ·
Hello guys,
Since the weather start being hot, I was trying to put my Ac on but it doesn't bring out any cold air it bring me air from outside, I opened the hood to check the AC Compressor and i found that the clutch doesn't engage with the polly when i put the AC on and i really don't know why it happened.
last summer the Ac was workin fine till i start use the heat.
i didn't make any mintainance in the motor but the V Belt only, does it make any problem to the compressor??
also if anyone could tell me how exactly i put the Ac on since it has autmatic climate just to make sure that i use it right way.

thanks in advance.:thumbsup:
 

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2001 E320; 2002 ML500
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1,982 Posts
The first thing you need to check is if you have enough refrigerant in the system. If there isn't enough, the compressor will not engage.
If you don't know how to check the system for proper operation, I suggest you take the vehicle to someone who is familiar with automotive AC systems.
 

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W124-94 E320
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Discussion Starter · #4 ·
okay,
I checked my AC refrigerant and it gives me 20psi, I know it needs more but i wanna know if that pressure is enough to let the compressor work or no?
thanks
 

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W124-94 E320
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Discussion Starter · #6 · (Edited)
good news,
i charge it up and you were right, The system was completely empty due to a crack in the AC High/Low Switch .
after fixing it and refill the system every thing worked fine.
thanks every one for help
 

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99 Merc S420 (80k Mi) 07 Lexus LS460 (21k Miles)
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4,583 Posts
good news,
i charge it up and you were right, The system was completely empty due to a crack in the temperature sensor.
after fixing it and refill the system every thing worked fine.
thanks every one for help
Did you put R12 back in the system and did you change the drier?
 

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W124-94 E320
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29 Posts
Discussion Starter · #8 · (Edited)
no my car has R134a that's what i saw in the owner manual, and that's what i put in the system actually, i didn't change the drier, should I?
 

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2001 E320; 2002 ML500
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no my car has R134a that's what i saw in the owner manual, and that's what i put in the system actually, i didn't change the drier, should I?
Any time the system is opened air goes in and the drier absorbs the moisture in the air rendering it useless. You need to replace the drier and vacuum the system prior to recharging it.
 

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W124-94 E320
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Discussion Starter · #10 ·
Sergio,
what about if I won't change the drier, Coz actually I checked the AC and it works fine.
If I kept the old one as is do you thing it might coz any problem coz if it will do so, I would change it, Otherwise I will change it later
Thanks.
 

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2013 E350 sedan, 2013 E350 cab, 1993 400E sold,1999 ML320
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2,454 Posts
It could cause problems, the fact you didnt put a vacuum on it after a repair is not a good thing.
 

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Discussion Starter · #12 ·
Okay, then could anyone please tell me what exactly should i do and what are the steps should i follow to replace it (provided with photos if possible)
Thanks for all
 

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1993 190e-2.3; 1992 300E-3.0, 1998 Saab 9000T
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107 Posts
Didn't you say in an earlier post the you charged it up and everything is working fine? Unless you opened the system, you don't need to change the receiver/dryer. Didn't you say there was 20 psi in the system?

You must have a slow leak and will need to get that fixed sometime. For now, if it is working and cooling, just leave it be.
 

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Discussion Starter · #14 ·
I had 20psi in the system but the compressor wasn't work coz of the low pressure, then when i start to charge up the system i found a leak coming through the AC High/Low Switch (it was broke) then i replace it with another one and i start charge up the system again, then right the way the compressor start working, i put about 2.5-3 bottle of R-134a then i check inside the car, i found the Ac works fine.
that's exactly what happened.
Now some members are saying i supposed to replace the drier, i really dunno if i should or no?!
and if i should replace it, then what kind of problem it might happen if i didn't replace it?
thanks
 

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1993 190e-2.3; 1992 300E-3.0, 1998 Saab 9000T
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If you didn't leave the system open for very long, it should be okay. The worst thing would be a decrease in efficiency. However, if you didn't use a vacuum pump before you charged it up, that would be a real problem. You will have a lot of air in the system. If you didn't vacuum it, I would get a receiver/dryer (pretty cheap), some o-rings, and replace it. Then vacuum it down to as low as you can get, hopefully -29 psi, and then charge it up without putting air back in. You really need a guage set to do it right, so you can get the freon in without loosing the vacuum.
 

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99 Merc S420 (80k Mi) 07 Lexus LS460 (21k Miles)
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If you replaced anything on the system (which you did), then you released the remaining 134a and exposed the drier to the outside air. The drier is now toast and useless. Think of it like a sponge being dropped in water. The drier is there to dry the system out as it works to cool the car. If the drier is filled then it can't work. I'm sure there is also a large amount of air in the system, which doesn't compress and de-compress well. With the combination of the air and the failed drier, you will be looking at a short lived A/C system. Your compressor will overheat and blow out with time. Those are not cheap or easy to replace.
Vacuum the system down, install a new drier, some new O rings and then recharge with fresh 134a. An exterior clean down of the condensor under the hood isn't a bad idea either. After 14 years, I'm sure its fairly dirty (unless it has already been replaced?).
 
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