My AC stopped working last year. We ran some tests on it and replaced the AC compressor, condenser and I believe other part on it. Tested for leaks but did not find any, but now a year later it is not working again. Thinking maybe evaporator. Wondering how difficult it is to replace the evaporator... can it be done well personally or does it need to be taken to a shop? Does the whole dash need to be undone to access it?

Thanks!

 

Legally, you must discharge an A/C system with a very expensive machine that recycles the R134A A/C coolant. You can depress the high or low side valves with a small tool, similar to the air intake valves on a tire. If you have no discharge at all, then you have a leak somewhere. Yes, the evaporator can be changed but it won't be easy and yes, you'll have to remove the climate control box to get at it, so "Does the whole dash need to be undone to access it" is a mostly true statement.

How do you know it is the evaporator at fault here? Is your magnetic clutch engaging the A/C compressor?

 

A few years back the AC in my TrailBlazer quit working so I put my gauges on it and discovered the high and low side pressures were 0, so I recharged the system. Two days later, the AC did not work again so I put the gauges back on, discovered the pressures were once again 0, and I then knew I had a big leak. I visually inspected the lines, the condenser, the compressor, all the joints, and I did not see any oily areas so I assumed the leak was in the evaporator. Since the TrailBlazer was under an extended warranty, I took it in and let the pros tackle it. Well, it did not turn out to be the evaporator. It turned out to be a hole in the condenser. I am happy that I was wrong, and I purchased a uV leak detection kit shortly thereafter.

I guess the moral of the story is don't assume it's the hardest part of the system to get to when it comes to automotive HVAC systems. Diagnose the problem using the appropriate tools. You just might find that the problem could be right in front of you and much easier (and cheaper) to repair.