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2005 Z51. Been out of town from July to January. Had the car at a friend and he took it for a spin every couple of weeks. Came back in January and all seemed fine. The other day it got hot outside and I turned on the AC on cold for the first time since I came back. Noticed it's not blowing cold at all. Brought it home, took the AC pressure gauges out, 0 psi on both low and high lines. Going to rent a compressor to do a vacuum test and refill. I can't find any stickers with refrigerant and oil info so the question is, should I put any oil in it? If yes, how much? How much R134 should I add?
Before you charge with refrigerant you need to locate the leak source. I know the 05 cars were over charged from the factory and a new weight charge was put out by GM.
Yes you need to find the source of the leak. I'm in the same boat - 0 psi refrigerant.
I did a visual but was unable to see evidence of a leak - the PAG oil usually leaves a telltale sign.
Often leaks are hard to find. Now I have to decide if I want to purchase a leak detector kit or go to a dealer to find the leak.
Be aware that once the leak is repaired, you have to vacuum the system for a few hours to get it all dry, and then add the refrigerant R134A and PAG oil.
If the compressor blew internally causing the leak, there might be bits of compressor internals throughout the system, so a flush of the system would be required first, or fragments will make their way into the new compressor.
If you are handy, change the leaky component yourself - GM dealera around here change $105/hr and some of the components (like the compressor) look like they will take some time to swap out.
Not so much fun.
M...
Last edited by Mike Green9; Apr 9, 2019 at 04:39 PM.
OK , just repaired mine, the condenser was the culprit. It was leaking at the very top and showed signs of it with a wet spot from the oil. You maybe able to see it from under the car looking at the outside towards the very top, but mine was more evident behind the condenser between the radiator. This is the area that a lot of leaves and crud builds up and create a hot spot and I think that's what caused my leak. I also gave it a small charge with the UV dye to check the whole system, the green spot was the size of my palm. Not much of a chance that a blown compressor with metal running through the system a flush is going to do anything for you, as the passage ways in the condenser are very small, the size of a pin. If the system was open to a lot of air and humidity, it is recommended that the condenser/receiver dryer be replaced anyhow.
Add oil using the chart that PDsvettes posted to each component replacement. The amount pre- filled with oil in the compressor is the total system volume. PAG46 is the type and 1.1 lb. is the correct total freon charge amount.
Last edited by extrapilot; Apr 9, 2019 at 05:23 PM.
Any idea how much oil to add in this case? I did not remove any parts, just that the freon is gone.
I did not add any oil when I charged with UV dye for leak testing. It's hard to estimate the oil amount loss with a slow leak.
I believe it's best to not add anything until you determine what needs to be replaced, again using the chart posted.
Definitely the easiest component to change in our ac system. Remove the air cleaner/housing from the mass air flow inlet connection, remove the 4 screws holding the top radiator plastic support, that will gain you access to the front plastic radiator/condenser shroud, look down 1 on each side is a plastic push type retainer, pry off with a screwdriver, most likely will break off, that will enable you to pull the top of the shroud away far enough to slip the condenser up and off the front radiator mounts . Of course, remove the ac lines first, the lower one access by jacking the front of the car up, right under the bumper cover, easy to get at. Inside the ac tube/line is a filter/screen, the tip is exposed enough to grab with your hand. Once it's out, you can get a idea of the condition of the ac system, replace if it's dirty, if it's gummed up badly, you may have other problems that will have to be dealt with. Add the oil to the top inlet port before installing, just makes it easier.
A/C system empty
