Auto A/C Terms - Glossary
Flush - Flushing A/C Systems

Flushing or cleaning the A/C system internally is one of the most important steps in auto A/C service to restore the system when there is any sign of contamination and specially after a compressor failure.

Understand that it takes less than one tenth of a teaspoon of debris or contamination in the A/C system to cause serious problems and possibly compressor failure. Contamination usually is a result of excess moisture in the system. When that moisture is mixed with refrigerant, a chemical reaction occurs which causes acids to form. Those acids are harmful and cause the A/C components to corrode and deteriorate internally.

In the case of a compressor failure, particles and pieces of the compressor will typically scatter throughout the A/C system. Those particles create a contamination that must be removed.

Understand that when debris and contamination are in the system, there is a good chance that they will restrict the flow of refrigerant. When that contamination plugs the expansion valve or orifice tube, not only is the flow of refrigerant closed off, but the flow of A/C compressor oil is also restricted. That means the A/C compressor is operating without proper cooling or oil.

Flushing the A/C system should be completed to remove all the contamination and contaminated oil. Remember that the debris will typically be held by the oil. Therefore, flushing must remove the oil. Refrain from using oil based flush solvents. They will not remove the contaminated A/C compressor oil that is in the system. Be sure to use solvents that are designed for flushing an A/C system. Those solvents will dry quickly and not leave any residue.