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A/C line freezing up?

Tiny
TONY02
  • MEMBER
  • 2001 HONDA ACCORD
  • 212,000 MILES
Upon recharging my A/C system I found out that the line at the evaporator is freezing up where the expansion valve is at the compressor is always engaged, but I’m able to turn it off and on with the A/C button inside the car. I will add some pictures below so you can see what I am talking about, but I am thinking it’s maybe the expansion valve not to sure though.
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Thursday, August 4th, 2022 AT 12:29 PM

13 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,708 POSTS
Hi,

If the system never turns off, it sounds like the AC pressure switch isn't doing its job. The switch is located in the condenser outlet (passenger side behind bumper cover). I attached a pic below showing the location.

The pressure switch is what will cycle the compressor. What I need you to do is check the switch to see if it is good.

Starting with pic 2 are the directions for testing it. Try this and let me know the results.

Take care,

Joe

See pics below.
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Thursday, August 4th, 2022 AT 8:40 PM
Tiny
TONY02
  • MEMBER
  • 70 POSTS
So, I replaced the pressure switch and it is still the same thing.
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Thursday, August 11th, 2022 AT 10:43 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,708 POSTS
Okay, the only other thing I can think of is if the refrigerant is a bit low. By chance, do you know both the high and low-pressure readings? If so, let me know what they are and what the outside temperature was when checked.

Let me know.

Joe
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Thursday, August 11th, 2022 AT 6:32 PM
Tiny
TONY02
  • MEMBER
  • 70 POSTS
When I have the switch off for the A/C inside the car The low pressure is 75 and the high-pressure side is 125 with the outside the temperature being 89°F and when I have the switch on the low-pressure side is 25 and the high-pressure side is still 125 with the outside temperature being 89°F. I’m starting to think it can be a bad compressor maybe because I don’t feel refrigerant flowing through the lines.
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Wednesday, August 17th, 2022 AT 7:38 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,708 POSTS
Hi,

With the vehicle off, the pressure should equalize. It may take some time. However, what you listed with it off doesn't make sense.

With the system on, the readings you listed indicate low Freon.

Let me know.

Joe
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Wednesday, August 17th, 2022 AT 7:57 PM
Tiny
TONY02
  • MEMBER
  • 70 POSTS
Yes, when the system is off the pressure is stable, but I recharged it again today and put 2 cans of 12oz of refrigerant and the car specs says the max is 22oz, so it’s not too far off.
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Wednesday, August 17th, 2022 AT 7:59 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,708 POSTS
Hi,

If there is enough Freon in it, then I agree the compressor seems to be faulty. Did the additional Freon make any difference?

Joe
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Wednesday, August 17th, 2022 AT 8:01 PM
Tiny
TONY02
  • MEMBER
  • 70 POSTS
No, not at all. The compressor still stays engaged all the time.
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Wednesday, August 17th, 2022 AT 8:02 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,708 POSTS
Hi,

If the system is fully charged, the compressor runs constantly, and the pressures are off, it does sound like a faulty compressor.

I don't know if you need it, but here is a link that explains in general how to replace an A/C compressor:

https://www.2carpros.com/articles/replace-air-conditioner-compressor

If you need directions specific to your vehicle, let me know what size engine the vehicle has.

Take care and let me know how things turn out and if I can help in any way.

Joe
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Wednesday, August 17th, 2022 AT 8:33 PM
Tiny
TONY02
  • MEMBER
  • 70 POSTS
So, I replaced the compressor and fully recharged it but now the pressure is reading really weird low-pressure side is in vacuum and high-pressure side is around 125.
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Sunday, August 21st, 2022 AT 10:34 AM
Tiny
TONY02
  • MEMBER
  • 70 POSTS
I already replaced the evaporator core with the expansion valve.
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Sunday, August 21st, 2022 AT 10:43 AM
Tiny
TONY02
  • MEMBER
  • 70 POSTS
I ended up replacing the accumulator and condenser as well but I’m still getting the same thing the low side is going into a vacuum.
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Sunday, August 21st, 2022 AT 1:48 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,708 POSTS
Hi,

Are you absolutely certain there is enough freon in the system? This happens when freon is low. It's got nothing to compress so it goes into a vacuum. That is the only thing I can think of.

Let me know.

Joe
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Monday, August 22nd, 2022 AT 7:52 PM

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