Automotive Air Conditioning Information Forum (Archives)

Jesus Freak on Tue August 12, 2014 11:42 PM

Year: 2001
Make: Chevrolet
Model: K2500 HD P/UP
Engine Size: 6.0
Refrigerant Type: 134A
Ambient Temp: 86
Pressure Low: 45
Pressure High: 180
Country of Origin: United States

Hi!

I just replaced a leaking high side port, and after adding freon the clutch stays engaged. The discharge pressure got real high (350-400), so I removed some of the freon and now the pressures are 180/45. The system is blowing cold, but there is no cycling and the clutch stays engaged. I did hear the pressure relief valve blow when the pressures were running high.

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Newbie w/ troublesome 2001 Chevy Truck AC

Dougflas on Wed August 13, 2014 6:32 AM

Best to start with recovering the freon nd weighing in the correct amount. At this point you're at now, you do not know how much is in the system.

GM Tech on Wed August 13, 2014 7:13 AM

High side too high- is there adequate air flow through condenser? Is clutch fan working? Sprinkle garden hose water on front of condenser to test system....

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Cussboy on Wed August 13, 2014 2:31 PM

Quote
Originally posted by: Jesus Freak
Hi!



I just replaced a leaking high side port, and after adding freon the clutch stays engaged. The discharge pressure got real high (350-400).


You DID evacuate the system before adding the refrigerant (which isn't freon, in your case), correct??? Because you didn't state that, that's important.

Jesus Freak on Thu August 14, 2014 7:08 PM

Quote
Originally posted by: Cussboy
Quote
Originally posted by: Jesus Freak
Hi!







I just replaced a leaking high side port, and after adding freon the clutch stays engaged. The discharge pressure got real high (350-400).





You DID evacuate the system before adding the refrigerant (which isn't freon, in your case), correct??? Because you didn't state that, that's important.

Nope. I know, I know, but I was told I could lower the pressure on the system enough, that I could swap out the port under slight pressure, which is what I did.

I know the proper way is to measure the amount. The system holds 2.5 lbs of "refrigerant", so I attempted to put in a little less.

Question: While adding the refrigerant into the low side (suction) port, the gauge reading was high even when I first started. Is that normal? Am I just seeing the pressure on the can?

Static pressure is ~ 100lbs on a 90 degree day.


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Newbie w/ troublesome 2001 Chevy Truck AC

webbch on Thu August 14, 2014 8:27 PM

You were told wrong. Need to pull a vacuum and charge into it.