A/C blows hot air?

2011 NISSAN MAXIMA
151,000 MILES • 6 CYL • 2WD • AUTOMATIC
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TANYAPEHRSON
  • MEMBER
  • 1 POST
Every part of the A/C system has been replaced. But when driving it's cold for a little while then gets warmer then blows hot air. I cannot find a leak. Sometimes after it sits for a while it will blow cool again then goes back to blowing hot.
Aug 13, 2023 at 12:43 PM
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STRAILER
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 54,178 POSTS
Does the system lose refrigerant? If so, then we need to find the leak.

This guide can help:

https://www.2carpros.com/articles/air-conditioner-leak-detection

If the system is full, I need to see the high side and low side pressures.

This video will help:

https://youtu.be/4EqdrBVb0sY

You may have a defective AC compressor, the system has too much oil or the system is low on refrigerant and the evaporator ices up, or the temperature blend door actuator is acting up. When the system is on, please grasp the large AC tube coming out of the firewall to see if it is cold when the system is blowing hot from the vents. I put a red arrow for where you should grasp the AC tube at. Check out the images (below). Please let us know what happens.


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Aug 14, 2023 at 4:46 PM
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