I have an 2002 E320 an live in the Florida Panhandle. I've been working with an A/C problem for a while. The A/C would take about 7 - 10 miles of driving for the compressor to kick on, then the driver's side would stay warmer then the passenger side. An inexperienced local shop put freon in the system based on pressure (Overfilled). It had the worse problems so took it to the dealer and they replaced the Duovalve and evacuated the freon and replaced it by weight. Got the car back and the same problems exist. I had previously got a refrigerant pressure sensor error, but had reset it and it never came on again. Took it back to the dealer and they just started replacing parts and charging parts and labor in a trial and error fashion. Got frustrated and decided to try the forum for some help. The issue with the compressor not starting has to be related to the Refrigurant Pressure Sensor (RPS). I started monitoring #7 while driving and when the the car is not cooling it reads 0, 1, or 2 bars. When the A/C is working it will read from 9 to 15 bars. When the freon was over filled it read from 22 to 34 and would kick thew compressor off when it was high. I'm pretty sure the sensor is working (#7). QUESTION: what controls the variable pressure in the 210 chasis. How is the pressure regulated? There is no freon leak and the car has the correct amount of freon. So what would cause the RPS to read low at times and normal at others.
Excuse me, but how come "0" can indicate proper amount of refrigerant (134 is not freon) ?
There are lot of threads running on the subject this time of the year, so take your time to read them.
You are low on refrigerant IMHO.
Welcome to the forum.
Have you ran the onboard diagnostics? How to Diagnose Air Conditioning Malfunctions | EclassBenz.com
run them at the directions Lex has for his program
also post the values for 1-8 and errors here.
someone will figure it out
Sorry about your experience with the dealer.A letter with your issues and what they did and charged you to not fix the issue is in order to mbusa in N.J
The dealer did evacuate the system and filled with 134A (Tetrafluoroethane) by weight, so the 134A level should be fine. I drove the car yesterday and the A/C worked all day!
Today my girlfriend drove it and the A/C isn't working at all.
Not sure what all her numbers were today, but she said #7 was 0 today. Just puzzling to me. One thing I noticed that when I stopped at a red light #5 would flucuate up to from 44 - 55. I noticed #3 (left heater core temp) generally runs 5 deg hotter then #4 (right heater core temp).
I've read all the posts I can find on the forums and most lead to low 134A or duovalve cleaning. I'll drive it again tomorrow and try to post some numbers when the system isn't running.
I don't believe the dealer added any dye to leak check. It was over filled by the previous auto technician we used. He wasn't used to working on a system like the Benz I guess. Normally he is very good. Not sure if he did a leak check either.
Our cars use a TXV rather than a fixed orifice tube used in most systems. That makes them harder to charge by using the pressures at the service ports. You can get them pretty close, but never exactly right.
Obviously, a leak check is indicated. If you remove one of the service ports and aim a UV lamp at the inside, it will glow if there is dye in the system. It will look like you have green oil in there if you look at it under fluorescent lighting. If you don't see anything, you can be pretty sure that there's no dye in the system.
You can get a dye injector and add some. Whatever you do, don't get the little can with the service port fitting built-in. I did and still haven't gotten the mess cleaned up. Get an injector that you can fill with pure dye and force it in with some refrigerant. They do sell the stuff to do this. I think I saw it at Auto Zone.
I would then charge it up and run it until it gets low, then look for leaks. Actually, I would vacuum the system down if it were already at 0, then add dye and refrigerant.
No o-ring conditioners, no sealers, just 134a and possibly dye. PAG-46 if you need oil, but a slow leak doesn't always release very much oil.
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