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Need Help with AC Problem

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Apr 8, 2021, 5:42 PM

Post #1 of 2 (576 views)
Need Help with AC Problem Sign In

2014 Silverado 1500 w/5.3L Ecotec engine.
Replaced the following:
Expansion Valve
Low side line w/two mufflers
High Pressure Switch

AC is cooling great, but having two issues:
1. whirring sound when ac is on-

When AC is running and I accelerate, I'm hearing a whirring or whining sound. It sounds like it is coming from the passenger side around where the evaporator is.

2. low side line frosting up where line comes out of expansion valve-

I have vacuumed and verified there was no leak when setting this up.

One of the things I have noticed is after the initial charge (around 25) the compressor clutch is engaged and I have not noticed the compressor cycle off and on again.

I'm learning that as a DIY, this AC fix is becoming more complicated then what I had anticipated.

I could really use some help, pointers, tips, etc.

Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Apr 8, 2021, 6:06 PM

Post #2 of 2 (568 views)
Re: Need Help with AC Problem Sign In

All AC repairs are more complicated than people think.

Expansion valve systems do not cycle unless the evaporator freezes.

If the noise responds to acceleration, then it has to be from the engine, probably the compressor.

There should be a freeze cutoff sensor/thermostat in the evaporator to cut the compressor off in the event of freezing


We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.

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