A/C not working properly

SHANETAYLOR337

MEMBER
2002 CHEVROLET TAHOE
5.3L
V8
2WD
AUTOMATIC
250,000 MILES

My A/C will blow nice and cold with good blow force for roughly ten to fifteen miles, then it just fades away and only hot air blows. Won't blow cold again until it sits overnight.I have put gauges on her and she is full of Freon. Compressor is not clicking on and off. Changed my fan clutch and the cut off sensor near the condensor. Im just a oil changing and simple parts changing guy and I have no clue what's going on with her, but I would sure like if anyone has advice. May be a minute before I can respond but I will check here every so often on feedback. Thanks a bunch.

5 Replies

KASEKENNY

MECHANIC
18,907 POSTS

Let's start with putting the gauges back on the system and then telling us what the pressure is when the A/C is off, then what the pressure is when the system is on.

The system should be cycling and the pressures should be responding so let us know what they go to when it clicks off.

Here are a couple guides that will help with this process:

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

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

If the compressor does not cycle then you may be freezing the evaporator so we need to keep monitoring the pressure when the A/C starts blowing warm.

So when it starts blowing warm, let us know what the pressure is and then check the A/C lines going into the firewall for frost and check the temperature of them to find out if they are still cold.

Below is a chart that will help with pressures based on ambient temperature and possible issues.

Please let us know what you find with this. Thanks

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Friday, June 25th, 2021 AT 6:47 PM

SHANETAYLOR337

MEMBER
11 POSTS

Thanks Kenny, I will be going to my buddys shop tomorrow. I will let you know what the gauges read and get back with you.

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Friday, June 25th, 2021 AT 7:02 PM

KASEKENNY

MECHANIC
18,907 POSTS

Okay. Sounds great. Thanks for the update. We will wait to hear back. Thanks again.

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Sunday, June 27th, 2021 AT 1:11 PM

SHANETAYLOR337

MEMBER
11 POSTS

Hey KaseKenny1, sorry for the gap in response, i'm on disability and had to save up to get some gauges, my buddy who normally loans me things of that nature has been busy, at any rate, here is what I found.
When my A/C was working properly of course the gauges read in the window of a working system however once it got warm, wich the length of time until warm varies from 15 minutes to an hour or so but when it does here's the readings, at 80 degrees the low pressure was 95, and the high was 110, the tubes going into firewall were actually warm not cool or frozen. Going by the chart looks like a compressor is what I need correct?I priced them and they are cheaper than I thought. If that's what is needed then I will have to get one.I have a lung condition and can't breathe in hot conditions. So what's your take on it?

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Wednesday, July 7th, 2021 AT 8:57 PM

KASEKENNY

MECHANIC
18,907 POSTS

This is signs of a compressor issue. Basically it is not able to build pressure. The only other thing would be a weak charged system so what was the pressure with the system static or the compressor, engine off?

https://www.2carpros.com/articles/replace-air-conditioner-compressor

Below is the info from the manual on how to replace the compressor.

Let us know and we can go from there. Thanks

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