Ac intermittent
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From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
Perhaps people with the problem losing a/c could measure what their low side pressure is and if it is “clogged” in the expansion valve and pressure is higher than 40 psi they can let refrigerant out. Mine has worked like this for 6-7 years so it seems to be kind of a permanent fix for the clogger expansion valve.
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From: V E G A S
1922 Ford Model T / no OBD
You did not do full troubleshooting, so you might have more issues.
If you are saying that for no reason high pressure jumps from 250 to 450 psi, that indicate problem.
Good if it works with your patch.
If you are saying that for no reason high pressure jumps from 250 to 450 psi, that indicate problem.
Good if it works with your patch.
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Joined: Oct 2010
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From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
The story what I’m telling is what happened to me with car that had not been serviced for the A/C at all before. I did not make this up.
I first thought there is a leak and added refrigerant as the low side pressure was lower than I’m used to with other cars before. Adding refrigerant made it worse so I let it out to the green area low limit on the gauge I had.
I don’t remember that gauge any more but now I have “professional” set of gauges and it tells me the pressure is below 40 psi on low side and it works well on two cars. I don’t believe it is a coincidence that two of my cars would have the same problem at the same time. I think these a/c systems are made to operate like this.
You could measure your own car a/c pressures but you don’t want to do that because it can cause valves to leak but I would not be surprised if you found similar pressures as mine if your a/c works well.
Last edited by Arrie; Jul 30, 2021 at 02:54 PM.
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From: V E G A S
1922 Ford Model T / no OBD
W212 and W166 are the 1st cars who will not display those values on the climatronic, so since they freeze my elbows in 120F weather, I am not touching it.
On my previous cars I had high pressure shooting up above 20 bars (300-400 psi) when pushed to max and once the cabin cooled down, it would operate in 12-14 bars range and having the display I often monitored that during driving.
As I concluded before, the system is pretty flexible and I had older AC cooling on single 12oz can of refrigerant.
Still there is difference between "OK" and "full performance".
One time I 'tested" overcharge and high limit was 32 bars, so your 450 psi might be just that.
Then overcharge at 450psi high would have 40-50 psi on low side, what you don't have.
On my previous cars I had high pressure shooting up above 20 bars (300-400 psi) when pushed to max and once the cabin cooled down, it would operate in 12-14 bars range and having the display I often monitored that during driving.
As I concluded before, the system is pretty flexible and I had older AC cooling on single 12oz can of refrigerant.
Still there is difference between "OK" and "full performance".
One time I 'tested" overcharge and high limit was 32 bars, so your 450 psi might be just that.
Then overcharge at 450psi high would have 40-50 psi on low side, what you don't have.
Last edited by kajtek1; Jul 30, 2021 at 03:33 PM.
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2008 E350, 2012 ML350, 2014 E350, 2015 ML350
Can someone (more skillful with TSB's than me) find the TSB mentioned in the video? It seems there is a suction-side hose problem with several models including the W212 and W221
Would a collapsed suction-side hose have similar symptoms as a clogged expansion valve?
Just my 2c for this thread.
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Joined: Oct 2010
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From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
Interesting picture. If that hose inner liner collapsed from vacuum in the system (and not when the hose was cut) it had to happen at the factory or at another time when the whole system was evacuated and then re-charged. That is the only time when there is actual vacuum present in any part of the system that could cause a hose to collapse like is shown in the picture. All other times after pulling vacuum in the system and then filling it with the refrigerant there is a positive pressure at every part of the system. Like that less than 40 psi in the low side that my cars like and then even higher for some other cars.
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MBWorld Fanatic!
Joined: Oct 2010
Posts: 5,142
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From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
https://youtu.be/FwIlOk_6HU8
Can someone (more skillful with TSB's than me) find the TSB mentioned in the video? It seems there is a suction-side hose problem with several models including the W212 and W221
Would a collapsed suction-side hose have similar symptoms as a clogged expansion valve?
Just my 2c for this thread.
Can someone (more skillful with TSB's than me) find the TSB mentioned in the video? It seems there is a suction-side hose problem with several models including the W212 and W221
Would a collapsed suction-side hose have similar symptoms as a clogged expansion valve?
Just my 2c for this thread.
40 psi low side pressure is the upper limit for my cars. I don’t think there is anything wrong with them other than charge was too high on the E550 when I lost the cooling years ago now and when I lowered it to get the cooling working again.
Thread Starter
Junior Member
Joined: Jan 2020
Posts: 18
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2012 cls 550
https://youtu.be/FwIlOk_6HU8
Can someone (more skillful with TSB's than me) find the TSB mentioned in the video? It seems there is a suction-side hose problem with several models including the W212 and W221
Would a collapsed suction-side hose have similar symptoms as a clogged expansion valve?
Just my 2c for this thread.
Can someone (more skillful with TSB's than me) find the TSB mentioned in the video? It seems there is a suction-side hose problem with several models including the W212 and W221
Would a collapsed suction-side hose have similar symptoms as a clogged expansion valve?
Just my 2c for this thread.
that was exactly my problem,
i think the engine mounts are shot and the engine lifts on hard accelerations causing the pipe to bend and over time the inner lining collapses and causes the system to stop working
i replaced the ac line, flushed the system then added denso ac compressor oil and the system is working for more than 2 years trouble free
thanks for everyone helping
payed a lot for troubleshooting and unnecessary parts
Member
Joined: Jan 2021
Posts: 94
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From: WA
2015 e63 wagon
@Jaycdayton Pardon my ignorance, but how do i check this blend door actuator?
I have recharged the AC to try to fix my "not cold enough AC" issue, but its unclear yet if something else might be broken.
I have recharged the AC to try to fix my "not cold enough AC" issue, but its unclear yet if something else might be broken.
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From: New Orleans Area
2015 E400 Sedan
how do you know itis properly filled and not under or over filled?
Maybe you have some AC error codes that canhelp?
What is actual lowest air temp out of center vents on MAX AC FAN HIGH and car being driven on interstate at steady speed?
What is ambient temp and humidity at this time?
Maybe you have some AC error codes that canhelp?
What is actual lowest air temp out of center vents on MAX AC FAN HIGH and car being driven on interstate at steady speed?
What is ambient temp and humidity at this time?
Newbie
Joined: Jun 2023
Posts: 4
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From: North Carolina
2005 ML500
Blend door
I don't have a shop manual for yours. You can Google to see which actuator is your blend. Or you can locate it yourself by removing lower panels, adjusting floor to defrost, watching the actuators move. 2 will move. 1 actuator is fresh/recirc on the right. Mine is hard to see, but I can lol through my lower heater vent and see the door. When adjusting temp, the door should move. 15 years in the shop I have found more pencils and pens caught in the blend door.© 2023 MH Sub I, LLC dba Internet Brands
Member
Joined: Jan 2021
Posts: 94
Likes: 42
From: WA
2015 e63 wagon
how do you know itis properly filled and not under or over filled?
Maybe you have some AC error codes that canhelp?
What is actual lowest air temp out of center vents on MAX AC FAN HIGH and car being driven on interstate at steady speed?
What is ambient temp and humidity at this time?
Maybe you have some AC error codes that canhelp?
What is actual lowest air temp out of center vents on MAX AC FAN HIGH and car being driven on interstate at steady speed?
What is ambient temp and humidity at this time?
MBWorld Fanatic!
Joined: May 2021
Posts: 2,527
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From: US
2008 E350, 2012 ML350, 2014 E350, 2015 ML350
Here is a summary what those labels would likely say. And I think the amount may also change depending on the AC code in the datacard.
https://bads.lt/en/mercedes-benz-ref...34a-an-1234yf/
https://bads.lt/en/mercedes-benz-ref...34a-an-1234yf/
Member
Joined: Jan 2021
Posts: 94
Likes: 42
From: WA
2015 e63 wagon
Did not find any labels with AC info on mine, but https://bads.lt/en/mercedes-benz-ref...34a-an-1234yf/ shows 640 gr while 1.5 pounds used by the shop is 680 gr.. will call it close enough for now 
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Joined: Feb 2007
Posts: 19
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From: Fredericksburg Virginia
Mercedes 2010 ML350 4matic
2010 ML350 AC quick connect coupler
I have 2 gauge sets and both work for my CLK320, but the high side coupler doesn't fit the high side of the 2010 ML350. It's a little smaller than the port on the car. Can anyone point out where can I get the right coupler for my car? A link would be very helpful. Thank you so much.
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From: Jakarta-Indonesia
2014 - W212.065 - E400 ( M276.820, 3 liter Turbo) RWD not Hybrid
I have 2 gauge sets and both work for my CLK320, but the high side coupler doesn't fit the high side of the 2010 ML350. It's a little smaller than the port on the car. Can anyone point out where can I get the right coupler for my car? A link would be very helpful. Thank you so much.
Or you get PARKER brand.
https://yellowjacket.com/product/aut...control-valve/
PARKER
https://www.unicorn-tools.nl/en/prod...adaptors/12107
https://www.unicorn-tools.nl/en/prod...adaptors/12108
I use Yellow Jacket, still made in USA version.
=======
There is also a possibility the pipe-hose set which has the high side service port is not genuine Mercedes parts and hence the port is not a good one.
I seen such issue on my favorite car HVAC Guru utube channel. R134a for automotive is international standard size.
So when the coupler is a good brand and the pipe-hose set is also genuine, it will fit 100% guaranteed
Last edited by S-Prihadi; Jun 21, 2024 at 03:30 AM.
