GLE350 AC blows hot air - possible compressor failure??
I had also noticed through some research of people conducting a Climate Control Reset by holding down the air recirculating button and defrost button at the same time while the key is in the #2 position. This didn't produce any results like described in the procedure. Is there a different procedure on this model that I'm not aware of?
Any advice would be appreciated before I bite the bullet and take it to the dealership for a $160 diagnosis.
The thermal expansion valve seems to be a potential cause. Google the thermal expansion valve, this has come up on this site before.
The valve is not available from MB but is available from normal A/C repair companies, and is FAR cheaper than a compressor replacement, but does require removing refrigerant and possibly unbolting the compressor for access depending on model and engine.
Replaced the control valve ($50 aftermarket part), which fixed the problem. You have to recover the refrigerant first, obviously, but swapping out the control valve was fairly straightforward. While it's technically possible to access the valve from underneath the car with the compressor in place on this particular model, it's very awkward/tight, access to the c-clip is hard to get to at that angle, and you may not even be able to pull the valve out as it's both quite stubborn and there is very little clearance. I ended up disconnecting the AC lines from the compressor and removed the compressor from the car completely in order to more easily remove the valve and reinstall the new one (it even took some work to get the new one to seat properly - it should eventually click into place and the c-clip should fit in the groove so that it spins fairly freely once seated. Anyway, a little fiddly, especially getting the old control valve out, but as long as you have new o-rings at hand there is really no good reason trying to swap out the valve without removing the compressor first.
Last edited by vsa; Apr 5, 2023 at 11:55 PM. Reason: solved the issue
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Replaced the control valve ($50 aftermarket part), which fixed the problem. You have to recover the refrigerant first, obviously, but swapping out the control valve was fairly straightforward. While it's technically possible to access the valve from underneath the car with the compressor in place on this particular model, it's very awkward/tight, access to the c-clip is hard to get to at that angle, and you may not even be able to pull the valve out as it's both quite stubborn and there is very little clearance. I ended up disconnecting the AC lines from the compressor and removed the compressor from the car completely in order to more easily remove the valve and reinstall the new one (it even took some work to get the new one to seat properly - it should eventually click into place and the c-clip should fit in the groove so that it spins fairly freely once seated. Anyway, a little fiddly, especially getting the old control valve out, but as long as you have new o-rings at hand there is really no good reason trying to swap out the valve without removing the compressor first.
Good Afternoon, any chance you have a part # or information on the correct control valve? I have a 2016 GLE 350 and wanted to try this before changing compressor. But oddly enough I am having a hard time very finding the part.
Thanks
diagnostic and says need a blend door under the dash will require 10+ hours to replace it. Part along is about $700 and labor is about $2400.
Does anyone have a DIY instruction or would Ryda's write up work...
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W211 Ryda posted an excellent write-up with details picture illustrations for E class.
https://mbworld.org/forums/e-class-w...rol-valve.html
diagnostic and says need a blend door under the dash will require 10+ hours to replace it. Part along is about $700 and labor is about $2400.
Does anyone have a DIY instruction or would Ryda's write up work...
================================================== ==============
W211 Ryda posted an excellent write-up with details picture illustrations for E class.
https://mbworld.org/forums/e-class-w...rol-valve.html
Here is how I caused the issue:
AC was not cooling as cold as It used to. I used two 134a cans and made sure the pressure was in the blue "filled" zone. Immediately I heard the system working harder and the vents no longer output any cold air. It was the ambient/heated air from under the hood.
Took it to a mechanic and he reduced the pressure from the low pressure side until it was at 60 psi.
The AC worked started cooling immediately!
Hope this helps someone, learnt that the GLE350 will not cool if the low pressure side pressure is too high.
Last edited by britoso; Sep 5, 2023 at 08:11 AM.




The 175/60 psi indicate wear our compressor, or control valve malfunction.
What's the mileage?
Than the description indicate that the system shuts AC off.
Do full troubleshooting.
Statt with sensors calibration test.
Go to the car on cold morning and without starting the engine, read all the temperature sensors.
Last edited by kajtek1; Sep 5, 2023 at 11:22 AM.




Here is how I caused the issue:
AC was not cooling as cold as It used to. I used two 134a cans and made sure the pressure was in the blue "filled" zone. Immediately I heard the system working harder and the vents no longer output any cold air. It was the ambient/heated air from under the hood.
Took it to a mechanic and he reduced the pressure from the low pressure side until it was at 60 psi.
The AC worked started cooling immediately!
Hope this helps someone, learnt that the GLE350 will not cool if the low pressure side pressure is too high.
These are not the old-school AC compressors.
On the high side pressure value, it should be around 180->200psi, and it should as good as new. The low side pressure should be below 50psi, but there are no adjustments possible.
There is ONLY one process:
1 - Take pressure measurements when at operating temperatures, and diagnose likely failing components. Check for leaks when under pressure
2 - Empty the system
3 - Replace failing components plus whatever else required for an open AC system, like dryer and sometimes condenser. Check oil in the compressor is up to specifications. Be certain to account for oil in the system if not flushed.
4 - Vacuum as low as possible, and as long as possible within reason (not just 5 min)
5 - Charge to the exact amount posted on the sticker, or find the original specifications
6 - Retest to verify fix is working as expected: low pressure < 50 psi, high pressure >180psi < 200psi. At least those are the ones I see in Florida at the peak of the summer. AC for the W212 and the two W166 are working as well as they can do.
7 - Repeat if the initial diagnosis was not successful.
NOTE: early 2023, 2012 ML 350 was not cooling great: Symptom: driver side warmer than passenger side.
First fix (late summer 2022)
1 - Low on refrigerant. Indy checked and refilled (I was not there, so I can attest to follow procedure)
2nd fix (late 2022)
1 - Not cooling well, refill again.
3rd fix (Jan 2023)- This is me now because of the two failed attempts ( https://mbworld.org/forums/m-class-w...ml#post8699414).
1 - Measured pressures at operating temperatures, and noticed abnormal behavior between low and high. Low pressure approaching 70psi under maximum load instead of dropping below 50psi. This is not the typical behavior, and is not listed on every AC check list.
2 - Diagnosed to electronic control valve. MB does not sell it. DENSO does not either, and Toyota's is different.
3 - Cross-referenced several ECV on eBay, and Amazon and finally found the "correct one"
4 - Follow the steps above, new ECV, new Schrader valves, charged to the sticker specified value
5 - Works great.
Last edited by JCM_MB; Sep 5, 2023 at 02:30 PM.
Replaced the control valve ($50 aftermarket part), which fixed the problem. You have to recover the refrigerant first, obviously, but swapping out the control valve was fairly straightforward. While it's technically possible to access the valve from underneath the car with the compressor in place on this particular model, it's very awkward/tight, access to the c-clip is hard to get to at that angle, and you may not even be able to pull the valve out as it's both quite stubborn and there is very little clearance. I ended up disconnecting the AC lines from the compressor and removed the compressor from the car completely in order to more easily remove the valve and reinstall the new one (it even took some work to get the new one to seat properly - it should eventually click into place and the c-clip should fit in the groove so that it spins fairly freely once seated. Anyway, a little fiddly, especially getting the old control valve out, but as long as you have new o-rings at hand there is really no good reason trying to swap out the valve without removing the compressor first.




The above us just a generic compressor for MB, yours may look different.
The electronic control valve is the one with yellow dot. Yours may not have the dot, perhaps a triangle or nothing at all. Location should be similar
Post VIN, a photo of yours if possible, and I try to find exact photo.
The above us just a generic compressor for MB, yours may look different.
The electronic control valve is the one with yellow dot. Yours may not have the dot, perhaps a triangle or nothing at all. Location should be similar
Post VIN, a photo of yours if possible, and I try to find exact photo.




I could not find a photo of these two options anywhere ( https://mbparts.mbusa.com/v-2016-mer...and-compressor)
You need to make sure you know exactly which compressor you have so you get the correct part. The one I ended up with is this one:
https://www.rkxtech.com/products/rkx...f25ace8e&_ss=r





