I just bought my S10 and noticed what seemed like a intermittent draw or load on the engine while cruising on the highway (over about 70-75mph) about every 30 seconds.Only for about 5 seconds.Only happens with AC on so figured it was compressor or clutch. At idle, clutch is engaged and spinning but if I gas it, clutch releases then reengages. I figure that the draw is the clutch kicking the compressor on and off. The AC is ice cold and the draw is "just noticable", not really causing any problems but strange so I just wanted to know if this is normal.
Thanks

 

yes it is normal, your compressor has a pressure switch located on the accumulator/ dryer. when the system pressure reaches a certain pressure it cuts the compressor off to avoid overpressurizing the system...