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Typical symptoms for clog on expansion valve.
Lowering the charge is a patch, who might last limited time.
Clog in expansion valve on both cars with similar results? I did the testing on my S550. I filled the E550 to 40 psi on low side pressure but I did not go driving it to see how it works.
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.
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.
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.
Yes, works well in two cars with the name Mercedes. Perhaps Mercedes a/c works with lower pressure than what is considered “normal”?
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.
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.
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?
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.
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.
Nice video. It shows the corrected system running 35 psi on the low side and says “about 180 psi” on high side. Exactly what my both cars do when the A/C system work very well that I have been trying to tell in my posts but for some reason this seems to be difficult to take by some.
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.
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.
hello,
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
Check your blend door actuator. Same issue I had. Starts off cold....as engine heats, warm air from heater core mixing. Easy to check, not so fun to replace.
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?
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?
Recharge was done by a shop and they determined its 1.5 pounds of R134 for my s212 e63... there is a notable improvement, but I didn't test in a properly hot weather yet
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.
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.
If you want a good r134A coupler , get Yellow Jacket, the one made in USA. I heard there is a China made version.
Or you get PARKER brand.
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
07-30-2021, 12:50 AM
