New R4 A/C Compressor GM New R4 - 6 Groove Clutch 4.25" Diameter, .85" Gauge Line - Metric Threads - 8mm Pin Coil @ 12 O'Clock 1991 -1993 New AC Compressor Buick Roadmaster Blazer C1500 Silverado Suburban Caprice K1500 Tahoe S10 1131875, 113188