Tile influence of materials selected for sliding couples, and the effects of seal design on overall seal performance in automotive air conditioning compressors were evaluated experimentally. Various carbon materials were investigated and dense, fine grained carbons were shown to give better performance. SEM analysis of the carbon materials provided insight to explain observed differences in performance levels. Comparative tests between a friction drive seal and an o-ring, positively driven style of seal, showed that the friction drive seal provided better performance based on minimizing oil and freon leakage. Oil and refrigerant leakage curves as a function of running time are provided for both seals for 600 hour tests.