I have a 2000 Tahoe. The air worked earlier this spring but then just stopped getting cold. I added one can of coolant but it didn't seem to help. It had a colorant in the can to help find leaks but did not see anything. I just added another can with a pressure gauge. The gauge reads about 45 psi when not running or when the vehicle is running but fan is turned off. Whenever the fan is turned on the compressor keeps turning on and off. When I have the gauge on it, it takes about 5-10 seconds to go up to 55 psi, then drops to 25 psi in a couple seconds, then back up, back down, etc. It does this with the fan turned on and doesn't matter whether the A/C is turned on or not.

I'm confused on this one. Any advice.

Your a/c system is low on refrigerant and that is why it "short cycles" as you've described.
I would recommend you take it for proper evaluation because simply adding more to a leaky system will not result in adequate performance. The systme needs to be sealed and vacuumed to remove moisture before it can perform as designed.

You definitely have a leak if you have a jiffy lube in your area take to them to have it leak checked and serviced if not take it to the dealer.


When adding it in you don't hearing any hissing sounds? Or unusual smells?

No, there are no apparent leaks anywhere. The first can of coolant I put in had some neon colorant in it. You can certainly see what sprayed out from hooking it up on the port but I see nothing anywhere else on the system and don't hear or smell anything.

If I was you I would definitely have a mechanic check it out.