Automotive Air Conditioning Information Forum (Archives)

ggenovez on Sun August 11, 2013 7:23 PM

Year: 1990
Make: GMC
Model: Burb
Engine Size: 350
Refrigerant Type: R134
Ambient Temp: 100
Pressure Low: -24
Pressure High: -24

Hi all,

My old compressor bit the dust so I replaced it with one from Napa. Replaced the orafice tube as well as the dryer.

I basically took off 4 connections. One of them or all of them or anyone in between has a leak. A tiny one but a leak non the less. I pulled a vacuum and got 24" and over night I lost all vacuum.

I tightened all the connections and I'm still loosing pressure.

What should I do from this point on? I want to fill it with R134. Should I put in 1 can with the leak detection stuff or just keep on tightening until I break something (I hate it when that happens).

Thanks

G

GM Tech on Sun August 11, 2013 7:26 PM

I usually add some charge and listen for a leak- or watch for the dye or use my leak detector to find the leak- it probably is not att he connections you broke- look elsewhere- do you have rear air? rear lines are always suspect.

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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......

ggenovez on Sun August 11, 2013 7:27 PM

Unfortunately no rear air. k. I'll check it out.

mk378 on Sun August 11, 2013 8:09 PM

Test under pressure with a small amount of 134a. If you don't have a leak detector you can put soapy water on suspected connections. Dye really only works with the system fully charged and running, which you don't want to do when you already know there is a big leak.

Also, o-ring based connections don't have to be very tight to make a seal. The ring is either going to seal or it doesn't. Overtightening the nut won't help anything.

Edited: Mon August 12, 2013 at 9:53 AM by mk378