Chevy 4500 AC Blowing Hot - HELP!

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Joined: Sat Aug 05, 2017 6:24 pm

Chevy 4500 AC Blowing Hot - HELP!

Postby Slumley1 » Sat Aug 05, 2017 6:32 pm

Hi! I've done a lot of research and am unable to figure out my problem. I recently purchased a 2010 Chevy Express 4500 w/ a shuttle bus on back. The ac hasn't worked since I bought it. I thought the rear ac was blowing cold when I tested but not sure and now no cold from either front or back.

The compressor was cycling on and off about every 10 seconds. I jumped the low pressure switch and the clutch released and the compressor was spinning. The gauge was reading under 10 psi. I added a bunch of r134a thinking it was just low. I added around 48 oz and the gauge read 40 psi. Still no cold air. I could feel different lines and coils under the dash and going through the fire wall that are ice cold but no cold air from vents. The blend actuator and door seem to work fine when I change temp.

​​​​​​​Any other thoughts?
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Joined: Mon Aug 07, 2017 3:13 pm

Re: Chevy 4500 AC Blowing Hot - HELP!

Postby Diametric » Wed Aug 09, 2017 7:23 am

40 psi on the low side or high side?

The low pressure lines will be cold for a moment after adding freon. Do they still get cold ten minutes later?

If the low pressure line still gets cold after about 10 minutes, then the compressor, evaporator and expansion valve are working to some degree and you should get cool air from the vents.

If not, then your problem is the fan and or blend actuators. Are you going by just sound or did you observe them working?
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Joined: Sun Aug 20, 2017 9:10 pm

Re: Chevy 4500 AC Blowing Hot - HELP!

Postby buiductuan1821 » Sun Aug 20, 2017 9:18 pm

well. This A/C , i too thinks that.

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