A while back I didnt use my aircon for a few months, as it was winter. The with the first warm days when I needed it, it didnt make cold at all. Took it to dealership: regassed, apparently no leaks. From then aircon does not make as cold as it use to (when it was still working - previous summer).

When I put my hand on the silver metal part of aircon pipe in engin compartment, it feels very cold. What I do feel, however (with my hand on pipe), is that the compressor is cycling on/off in about 30sec intervals.

I read somewhere that if "cold" is not removed from evaporator eficiently, it will also cut out (although "cold" is availible, it cannot be transfered to cabin). That why I thought evaporator may be dirty or something.

What else could it be?