Air conditioning system not accepting full charge

Tiny
GPAOLO
  • MEMBER
  • 2012 NISSAN VERSA
  • 1.6L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 120,000 MILES
System was tested for leaks and vacuum pulled to 30 for 45 minutes. Compressor kicked on almost immediately after beginning charge. Specs call for 14 oz of R134a. Freon stopped flowing at around 7 oz with low side steady at 50ish psi and high at 230ish. Ran in this state for 15 minutes or so with compressor steady on with no cooling. Compressor finally kicked off an pressures equalized around 80 psi. High side tubing gets quite hot. Low side warm. Compressor won't engage now. :(
Saturday, October 24th, 2020 AT 8:33 AM

5 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Take a look at this attachment. You have a blockage in the system and it is most likely the condenser. If the compressor was creating pressure like it was but you are not getting cooling it is because the condenser is blocked and not cooling the Freon to create the temperature difference.

Did you just replace the compressor or make a repair to the system? If so, I bet there was metal in the system and it clogged the compressor. My only worry is that the compressor has no failed due to the this. So I would replace the condenser and receiver dryer then retest the compressor. You will need to evacuate the system again and hold a vacuum and then recharge it.

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system
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Saturday, October 24th, 2020 AT 2:47 PM
Tiny
GPAOLO
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Thanks Kenny, initially the problem was merely cool air instead of cold when rolling and barely cool when parked. The compressor was cycling on for no more than 5 seconds at a time and off for about 90 seconds. Self declared master mechanic that I am, I thought I'd just add a "little" Freon. I add 6oz or more with no effect before I figured that was a bit much. Pulled out the gauges to find that during those 5 seconds on, the high side was building to 370ish then shutting down. After a minuet or two high side fell and compressor kicked on and repeated. I can't recall the low side value. During this testing my el-cheapo gauge connector leaked and evacuated the system. :( That's when I pulled vacuum with good gauges and attempted the recharge.
Any chance it's the expansion valve? And you said maybe there is metal in the system. How can that happen? And thanks for the info on changing the condenser. Is there any way to test the condenser before pulling it?
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Sunday, October 25th, 2020 AT 1:25 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Based on what you were seeing the condenser is more likely but if you want to do the expansion valve first, that would not hurt. However, I normally change that anytime I replace a part on the system because they are cheap and not to hard to change and since the system is open for the other part, I just put a new one in.

The way metal gets in the system is from the compressor. However, with that info, it sounds like the compressor is just fine. If it is building to almost 400 then you have a restriction. If it were me, I would change the condenser and expansion valve and then pull a vacuum again and recharge it. There is no real way to test it for a restriction other then to remove it and put some compressor air to it. The pressures are the real way to tell and that is where I would start.
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Monday, October 26th, 2020 AT 6:40 PM
Tiny
GPAOLO
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  • 9 POSTS
Thumbs up Kenny, it's my college student daughter's car so I will put it off until Christmas break and I will follow your recommendations. Thanks a bunch. Will post results when I tackle the job.
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Tuesday, October 27th, 2020 AT 9:47 AM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Sounds great. Thanks for the update. We will be here whenever you get back. Thanks again.
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Tuesday, October 27th, 2020 AT 8:19 PM

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