A/C compressor pressures?

Tiny
GMANSCHULT
  • MEMBER
  • 2011 TOYOTA COROLLA
  • 1.8L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 115,000 MILES
No movement on gauges until 2 minutes after I start the car. Pressures stabilize at 150 high 50 low. A/C is cold until about 90 degrees then starts to blow only cool air, not cold. A/C condenser fan is working in high mode. I have the condenser fan jumped to 12 volts as it wasn't kicking on high for a reason I don't know. Maybe the compressor is going bad, maybe solenoid valve. Hopefully you can help shed some light on it.
Wednesday, August 3rd, 2022 AT 11:57 AM

7 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,055 POSTS
Hi,

It sounds like either the compressor is failing, or the compressor clutch isn't fully engaging.

I question the pressures. If the ambient temperature was 90 degrees F, the low-pressure reading you have is perfect, but the high pressure is very low. I would expect it to be around 250 PSI to 270 PSI.

When the system starts to build pressure, are there any odd sounds you are noticing? Also, take a look through this link and let me know if anything helps:

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Let me know.

Take care,

Joe

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Wednesday, August 3rd, 2022 AT 8:13 PM
Tiny
GMANSCHULT
  • MEMBER
  • 4 POSTS
Hi Joe, thanks for the reply. The compressor is quiet as a mouse, no strange noises. The temperature was 87 when I got those pressures. I believe my compressor is variable displacement. On cloudy days it works great, but when the sun comes out or in the heat of the day it barely keeps the car cool. Thanks again.
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Wednesday, August 3rd, 2022 AT 8:43 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,055 POSTS
Hi,

If it is variable, I would still think the high pressure would have been higher, especially if it wasn't cooling and the temperature was near 90.

Do me a favor. Let me know if the system has automatic climate control or manual control. I want to read through the diagnostic info, but it goes two different ways based on the system. See pic below

Let me know.

Joe

See pic below.
Image (Click to make bigger)
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Thursday, August 4th, 2022 AT 4:24 PM
Tiny
GMANSCHULT
  • MEMBER
  • 4 POSTS
Hi Joe. It is manual.
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Thursday, August 4th, 2022 AT 7:29 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,055 POSTS
Hi,

Thanks. I went into the manual diagnostics and found nothing. See pic 1.

Since it takes a couple of minutes until the pressure builds, my first suspects are low refrigerant, or the compressor is failing. The compressor itself would be more likely with the pressures.

Have you tried vacuuming the system down and then recharging it?

Let me know.

Joe

See pic below and sorry for the manual's lack of help.
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Thursday, August 4th, 2022 AT 10:23 PM
Tiny
GMANSCHULT
  • MEMBER
  • 4 POSTS
Hi Joe. I fixed my A/C today. I changed out the solenoid valve and my pressure returned to normal. At 85 degrees I'm now getting 35 low, 210 high and cooling at 50 degrees. Thanks for your help.
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Friday, August 12th, 2022 AT 9:23 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,135 POSTS
JACOBANDNICKOLAS is one of our best! Use 2CarPros anytime, we are here to help. Please tell a friend.
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Saturday, August 13th, 2022 AT 12:31 PM

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