2014 GMC Sierra 5.3 - 0 psi low side normal pressure high side

[Sinuous1]

0 psi low side normal pressure high side. System was evacuated appeared a little low on R134A, recharged to no avail and the compressor is engaging with no crazy sounds. Worked fine driving to the fire station and 2 days later blowing hot air in AZ....currently 115 degrees. Help. I've already previously replaced the condenser and installed the fix bracket around 75K miles ago. Any ideas?

[Snowcamo]

Charge to full capacity and leak search the systems service ports and connections. Possible the condenser coil.

[Buckwild27]

Add some dye to the system when you charge it up again. Once it works it's way through the system you can get a UV light and look for the dye leaking out. 

[rlcole321]

first, are you sure it uses R134A and not R1234?, second, if the low side is reading 0 psi, then the compressor shouldn't be coming on, low side pressure switch should keep comp. off.  Possibly your gauges low side connector is not pressing open the Shrader valve. Now with only 30 to maybe 40 degrees difference in incoming and outcoming air from the evaporator, at 115 degrees outside, you may be only getting 85 degree air coming thru the vents.  with the AC on, is the low side line coming out of the evaporator feel cold or cool?, if so then there is some low side pressure.

[newdude]

16 minutes ago, rlcole321 said:

first, are you sure it uses R134A and not R1234?, second, if the low side is reading 0 psi, then the compressor shouldn't be coming on, low side pressure switch should keep comp. off.  Possibly your gauges low side connector is not pressing open the Shrader valve. Now with only 30 to maybe 40 degrees difference in incoming and outcoming air from the evaporator, at 115 degrees outside, you may be only getting 85 degree air coming thru the vents.  with the AC on, is the low side line coming out of the evaporator feel cold or cool?, if so then there is some low side pressure.

 

 

2014 Silverado would use R134A.  GM didn't start switching in the pickups until 2017 or so to R1234yf.  

[newdude]

On 7/3/2024 at 6:11 PM, Sinuous1 said:

0 psi low side normal pressure high side. System was evacuated appeared a little low on R134A, recharged to no avail and the compressor is engaging with no crazy sounds. Worked fine driving to the fire station and 2 days later blowing hot air in AZ....currently 115 degrees. Help. I've already previously replaced the condenser and installed the fix bracket around 75K miles ago. Any ideas?

 

 

Have it properly charged and leak dye added and check for leaks with a black light.  I wouldn't be surprised if it was a bad condenser again.  Could also be the compressor to condenser line.  temp.xml (nhtsa.gov)

 

 

Edited July 5, 2024 by newdude