The dryer does exactly what the name implies, it removes moisture from the refrigerant. It also holds refrigerant oil. R0134A inhibits moisture. It is worse than R-12 freon
My rule is to replace the dryer anythime the system is opened to atmosphere. Moisture causes internal A/C issues especially the compressor and reduces cooling efficiency.
There is no rul that I know of after 40 + years as a garage owner to replace the dryer every 3 years except as a sales gimic.
Wednesday, May 10th, 2006 AT 4:51 PM