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Polyalkaline glycol is used as the lubricant with R134a in automobile air conditioning systems and it is well known that polyalkaline glycol oil is highly hygroscopic in nature. Presence of moisture in the system may deteriorate the system and its performance. Hence polialkaline glycol oil is replaced with conventional mineral oil. In the present study, a new refrigerant blend R134a/R290/R600a with mineral oil as lubricant has been tested in an experimental test rig with R12 as base line and compared with the published results. Pull down test from an average cabin temperature of 50 °C is performed while the compressor speed is varied successively from 1500-2250-3000-800 rpm with a constant heat load of 2500 W, and held at that speed for duration of 30 minutes. Both R12 and the HFC-HC blend is tested in an experimental test rig and it has been found that this new mixture is almost in par with R12, However, a slight loss in system performance is encountered. But, considering the service issues associated with R134a and polyalkaline glycol oil, this new mixture can have better performance than R134a and polyalkaline glycol combination. [ABSTRACT FROM AUTHOR]