Air conditioner blowing hot air

2011 MAZDA CX-9
137,000 MILES • 3.7L • 6 CYL • 4WD • AUTOMATIC
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VROMANO88
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AC compressor clutch is actuating, thought it was low on refrigerant so bought an AC pro kit, hooked it up to the low side port and with the AC on full blast, car on, and AC clutch engaged it showed 100psi.
Jul 6, 2018 at 7:35 AM
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AL514
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Hello, a 100psi is way too high for the low side port, it sounds like you may have a restriction in the system. This can happen when the expansion valve goes bad or the receiver drier, but do not put any more refrigerant into it. The system needs to be looked at. Here is a little guide that will give you an idea how the A/C system works, but that low side pressure should not really go over 40 to 50psi.

https://www.2carpros.com/articles/how-a-car-air-conditioner-works
Jul 6, 2018 at 10:04 AM
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VROMANO88
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Thank you for your reply, I think it is a bad expansion valve for sure. Unfortunately on my car, the expansion valve is inside a large plastic HVAC casing under the dash so it is going to require a good amount of time to reach it.
Jul 9, 2018 at 5:32 AM
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STRAILER
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Before we dig in, it could be a bad compressor not pulling down we need to check the high side. Here is a guide to help you see what to do:

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

Please run down this guide and report back.

Cheers, Ken
Jul 14, 2018 at 10:59 AM