A/C having issues?

RLPETERSON78

MEMBER
2001 CHEVROLET SILVERADO
0.6L
V8
2WD
AUTOMATIC
180,054 MILES

Last Summer I had issues with my air conditioning in my truck. I put dye in the R-134a and discovered that the compressor was leaking. So, I replaced the compressor, dryer and office tube. That fixed it and I had cool air.

My truck was out of commission with a no crank no start. It took me a few weeks to fix it (thank you Joe). The problem was a broken ground wire to the starter relay. I have been driving it around and the air conditioning isn't working. So, I put my gages on, and I had 20 on the low side and 20 on the high side.

I looked for a leak using a spray bottle filled with dish soap and water used that to find any leaks, with the truck running and with it off and I didn't find any leaks. The low side was 20 and the high side was 20. I had a can of R-134a so I added some to the low side. That brought up the low side up to 30 and the low side didn't budge.

Last Summer I know that I put the proper amount of R-134a and oil in the system. And I confirmed I didn't have any leaks when I vacuumed the system before I added the R-134a. See the video.

Images (Click to make bigger)

1 Reply

STEVE W.

MECHANIC
13,443 POSTS

It sounds like you have a low charge and that is preventing the compressor from engaging.
20-30 psi in a static system is low unless you are in an area where the temperature is around 50-60 degrees. I suspect you have a leak now even if you didn't before. It is common for them to leak around the edges of the condenser and even out the port valves. Maybe look with UV as you had dye in the system. Don't forget to look in the A/C drain tube as well.
A very quick way to tell would be to jump power to the compressor and see if the high side goes up to normal. The image is a temperature and pressure chart to give you an idea of what you should see. If the high side goes up to say 130 but the low side drops below 20 it's a low charge, I would then recover the refrigerant and hunt for leaks under both vacuum and pressure. Then recharge with 1.8 pounds (28.8 ounces or 29 and the other.2 lost in the hoses) of 134A.

Image (Click to make bigger)