My dad owns a 2002 Chevrolet Avalanche 1500 with ~190k miles and an automatic transmission. His A/C didn't work when he first got the truck (~10k miles ago) so i refilled the system which had almost no coolant in it (I put in a can of r134a with sealer). The A/C was ice cold and working great, after a long road trip it started acting spotty, blowing cool but not cold. Now, the A/C still blows cool but it's noticeable at idle it's significantly warmer, when it's revved (doesn't have to be moving), it blows cooler but still not as cold as it should. I haven't taken a look at the condenser for any debris. I figure it's a weak compressor but I wanted a second opinion. Any thoughts? Thanks.
What was the "sealer" you put in? If it was a stop leak, then that may have caused blockages or damage. If it was a treatment for rubber seals, you may be okay and the problem is a leak. That stop leak stuff is horrible for air conditioners and usually "bricks" them. Put refrigerant with leak dye in, and run that. It's a 19 year old truck, the condenser may have holes in it. My 1999 Ranger had pinholes all over the condenser before I repaired it last year.
InterDynamics AC Pro Car Air Conditioner R134A Refrigerant, Reusable AC Recharge Kit, 12 Oz, ACP102-6
Will put leak dye in it, thanks for the advice.
That stuff is poison for car AC systems.
What system pressures are you seeing when you hook up your manifold gauge set?
You can't "fix" an AC system with a can of refrigerant laced with potentially destructive sealer and equipped with a useless "fill to the green" low-side gauge. You most likely have a leak that the "sealer" did not fix. Pray the stuff does not solidify inside the expansion valve, compressor, or somewhere else in the AC system where it will play havoc as it did for a friend who tried that stuff in his Toyota and wound up having to replace everything because of all the parts it gummed up.
https://www.youtube.com/watch?v=_IBFLMYZEzI
That's the exact video I watched when I learned to service the air conditioner in my Ranger. The video I actually used in real life, haha.