Comparative Test results between a prototype low pressure automotive air conditioning system using isoamylene as a non-fluorocarbon refrigerant and a control vehicle equipped with a well-developed production R-12 system are reported. The performance of the new system was favorable. The low pressure Rolling Vane compressor used in the test vehicle is described. The remaining system components, which were derived from existing technology and hardware, are briefly discussed. As well, a summary description of the design and analysis procedures for the individual components is presented.