Air Conditioning Problems

[razziel24]

Hello, i have a 2019 ST with 72k miles.

A month ago I started feeling like the AC wasnt blowing cold air, sometimes air temperature would vary depending on the car speed or rpm.

I noticed that when I turn the car on, the air would not come out cold with the car standing still, but I have to drive it in the highway to start feeling like the A/C is really doing its job and cooling the air.

It turns really bad in traffic or in rainy days, I heard from some mechanic that there is an electronic valve in the compressor that fails, and when it happens, the A/C behaves like i mentioned.

Any of you had this issue ?

[razziel24]

anyone ?

[1004ron]

Based on the AC working when at speed, I'd suspect that the radiator fan isn't working and/or the grill louvers aren't working.

[razziel24]

Thank you for your answer.

It seems like they are working properly

For example, when i pick up my child from school, i sometimes wait 25 minutes with the car idling and AC on, and it keeps working fine.

 

[1004ron]

42 minutes ago, razziel24 said:

Thank you for your answer.

It seems like they are working properly

For example, when i pick up my child from school, i sometimes wait 25 minutes with the car idling and AC on, and it keeps working fine.

 

Wouldn't that be much the same conditions as "It turns really bad in traffic"?

 

Quote

I heard from some mechanic that there is an electronic valve in the compressor that fails, and when it happens, the A/C behaves like i mentioned.

 

Could that mechanic elaborate on this valve, like where it's at and cost to replace?

[razziel24]

He mentioned an electronic "compressor valve", and told me that the simptoms related to its failure, are similar to the ones I was describing.

It was just a casual conversation, he hasnt seen the car yet, but I wanted to check if this was a common failure.

Doing some online research i found this...

 

[razziel24]

and this is what "Gemini AI" told me about it...

 

Since your 2019 Ford Edge ST uses a variable displacement compressor, it doesn't rely on a traditional "on/off" clutch for every cycle. Instead, it uses an Electronic Control Valve (ECV) to regulate how much refrigerant is being pumped.

When this valve fails, the symptoms are often more subtle than a total system breakdown. Here is what to look for:
1. The "Delayed Cooling" Effect
The most common symptom is that the AC blows warm air for the first 5–10 minutes of driving, and then suddenly begins to blow ice-cold. This happens because the valve is sticking and requires enough vibration or pressure buildup to finally "pop" into the correct position.
2. Inconsistent Temperatures
You might notice the air getting warmer when you are idling at a stoplight, then getting cold again once you start moving or increase the engine RPM. A failing valve struggles to maintain the correct displacement when the engine speed changes.
3. "Laggy" Response to Controls
If you turn the AC to "MAX" and nothing happens for a significant amount of time—even though you can see the compressor hub spinning—the valve is likely failing to adjust the internal swashplate to increase the stroke of the pistons.
4. Normal Pressures, No Cold Air
If a mechanic hooks up gauges and sees that the Static Pressure is fine (meaning you have enough R-1234yf refrigerant), but the High Side doesn't go up and the Low Side doesn't go down when the AC is turned on, it usually points directly to the valve rather than a leak.
5. Rattling or Clicking Noises
Because the valve controls the internal "tilt" (swashplate) of the compressor, a failing valve can cause the internal components to sit at an awkward angle, leading to a faint metallic rattling or rhythmic clicking coming from the compressor area.  

Pro-Tip for the Edge ST
Because the Edge ST's engine bay gets very hot, these electronic solenoids are prone to heat-soak failure.
The "Cheap" Fix: Many shops will tell you that you need a brand-new compressor ($800+). However, on many Ford compressors, the ECV is a replaceable part that costs around $40–$60.
The Catch: You still have to evacuate the refrigerant to change the valve, so it's a job for a shop with a recovery machine.

[1004ron]

Agree, the variable displacement compressors symptoms are very different to the ON-OFF clutch type.

[Davidoo]

Much of this issue could also be attributed to a low refrigerant level.  As the car runs a while and gets hot, the refrigerant expands as it heats and can work better.  It certainly could be the valve, but buying a refrigerant pressure gauge at an auto parts store and checking the level/pressure while its running could rule this out.  Even without a major leak, refrigerant levels do drop due to evaporation through the hoses and tiny leaks at the fill valves on the high and low pressure side.  If it is low, adding some gas could get you 5 plus more years without a problem.  

[Samurai Edge]

22 minutes ago, Davidoo said:

Much of this issue could also be attributed to a low refrigerant level.  As the car runs a while and gets hot, the refrigerant expands as it heats and can work better.  It certainly could be the valve, but buying a refrigerant pressure gauge at an auto parts store and checking the level/pressure while its running could rule this out.  Even without a major leak, refrigerant levels do drop due to evaporation through the hoses and tiny leaks at the fill valves on the high and low pressure side.  If it is low, adding some gas could get you 5 plus more years without a problem.  

I was leaning towards this answer.

 

It could be the valve, but it may also be a small, very slow leak that you will never find on your own.  The only way to find the leak itself is to perform a dye test, where they inject a dye into the A/C system.  The leak will show under ultraviolet light.

 

Sometimes the seals dry out causing the leak over time, eventually resulting in total cooling failure ( No A/C ) due to complete loss of refrigerant.

 

I had very similar symptoms on a couple of different brand cars over the years.  Acted just as you initially described.  It was a leak.