The AC Accumulator/Drier in an AC system is a very important part, it keep the system clean and free of moisture. When doing any work on an AC system it is important to remember to change this part out for a new one any time there is AC system work done. In an AC system moisture and debris can be detrimental to the functionality of the AC compressor and indeed the whole system. Debris in the system can travel through the system under pressure and tear up the seals from the inside. Moisture in the system can also cause issues, inside an AC system the oil and Freon have specific characteristics that they both follow. AC systems are designed to work with the specific movement of the oil and Freon, water and air act different under pressure. The AC system is a very intricate system and must be maintained properly.
When doing AC work on a car it is important that the Drier be changed any time the system I opened up. Why is it so important? The drier is the piece in the AC system that will capture debris and moisture in the system. When an AC system is opened debris and moisture can enter the system and must be captured by the drier. The old drier holds all the debris that it captures and if the pressure is released in the system then the system is recharged it can force debris out of the drier into the system. The debris released from the old drier can be as dangerous to the system as anything that may have entered the system.
Remember that even if you changed the drier on your car 3 days ago it is still important to change it again if you have to open the system today. Debris can destroy the internal workings of an AC compressor even if it is only 1 day old. So save yourself the headache and the calls to the parts suppliers about a bad compressor and keep the system working properly with a new drier. A new drier will protect the system and will keep your warranty active with most companies since in most cases, no drier, no warranty.
