2013 Sentra AC problem. Compressor turns on but high pressure = low pressure

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richietlc
Posts: 2
Joined: Mon May 14, 2018 4:59 pm

2013 Sentra AC problem. Compressor turns on but high pressure = low pressure

Postby richietlc » Mon May 14, 2018 5:05 pm

2013 Sentra AC problem. Compressor turns on but high pressure = low pressure. Ambient temps outside are 88 F.

My high side and low side are both showing 85 PSI. I verified that the clutch is spinning which should mean the compressor is working. I just replaced the compressor also and the symptoms are the same.

It has the correct charge. It is very weird that the compressor is spinning *i can see the clutch spinning* and the pressures are not changing on the high or the low. Also, if i turn the AC off, the pressure stays the same 85 PSI.


A friend told me the try changing the expansion valve but I do not know what to do now... I have experience with ACs, I did a full vacuum and charge with ac oil when I replaced the original compressor yesterday. Everybody online says if the pressures do not change the compressor has failed but this is a second compressor i JUST installed so its not the compressor. Also there are no funny noises.


Any help would be appreciated please. :?: This car only has 60k miles.
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Cusser
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Joined: Sun Apr 24, 2016 6:29 am

Re: 2013 Sentra AC problem. Compressor turns on but high pressure = low pressure

Postby Cusser » Tue May 15, 2018 5:28 am

richietlc wrote: I verified that the clutch is spinning which should mean the compressor is working. I just replaced the compressor also and the symptoms are the same.


The AC clutch can - and should spin - but it's the engagement part, the CENTER part spinning that's important.

If you weren't getting a pressure differential, how did you get a full charge of refrigerant in ????
richietlc
Posts: 2
Joined: Mon May 14, 2018 4:59 pm

Re: 2013 Sentra AC problem. Compressor turns on but high pressure = low pressure

Postby richietlc » Tue May 15, 2018 8:20 am

Cusser wrote:
richietlc wrote: I verified that the clutch is spinning which should mean the compressor is working. I just replaced the compressor also and the symptoms are the same.


The AC clutch can - and should spin - but it's the engagement part, the CENTER part spinning that's important.

If you weren't getting a pressure differential, how did you get a full charge of refrigerant in ????




Hey thanks for the reply! So, I charged about 10 oz of R134a which is not a full charge but it should be enough for the system to turn on and the pressure to differentiate. Hmm, I am going to look at the center part and let you know later on today if its spinning or not. I had no idea that there was a center part that should be spinning along with the clutch, I thought it was all in sync!


Also there are no leaks in this system. Also, I remember how I charged it initially. After the vaccuum, I pumped about 7 oz freon into it. Then waited 10 minutes, then started the car and turned the AC on(it was blowing warm). Then as I added the other 3 oz, I remember the Low vapor line got really cool and the air was blowing cold so I was thinking its good..*then it started to pour rain* so I turned the car off and stopped charging the system. Then, I came back to the next day and started the car expecting there to be a pressure difference like a normal undercharged system but it was behaving this way, so since then I havent bothered to add more refrigerant. All in all, the system has about 10 oz of refrigerant. Also, if there was a severe undercharge, I do not think the clutch would spin at all.
cool2bcool
Posts: 11
Joined: Sun Jun 11, 2017 10:10 am

Re: 2013 Sentra AC problem. Compressor turns on but high pressure = low pressure

Postby cool2bcool » Tue May 15, 2018 8:59 pm

like cusser said, also make sure you are getting a good connection with your quick connectors on the service ports and that both the knobs on the quick connector are turned fully CLOCKWISE. and make sure both knobs on your manifold gauge set itself are closed when checking pressures. If you look under the hood and have the car running without the a/c on, and then keep looking at the a/c compressor (seeing the front of the pulley) while someone hits the a/c switch you should suddenly hear a type of click and the piece on the front of the pulley which was once stationary will now be turning.

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