We finally got a few warm days here in Ohio and of course my air conditioner is blowing warm air even on the coolest settings.

This happened about three years ago and after replacing the refrigerant and adding colored dye, my Volvo dealer determined that the evaporator was leaking.

I had them replace the evaporator and the system worked fine, although it seemed to be getting a little weak last summer.

Is it possible (probable) that the replacement evaporator has sprung a leak?? Didn't Volvo improve the evaporator unit after having so many failures? Or is it something else (hopefully less expensive)?

I'm open to all advice. Some local auto parts stores are carrying R-134 recharge kits, some with just R-134 and some with sealer and oil. I'm tempted to try the plain R-134 although they don't have the lubricant. (Is this ok?) My understanding is that it's better not to use the products with sealer because it contaminates the system (and the machinery of anyone who might service the air conditioner in the future).

Thanks in advance for your help.