when i kick on my ac it does cause a little extra drag on my engine that is slightly noticeable - the rpm's go from 600 to about 750 at idle and it makes my exhaust sound just a little meaner - no difference in temp gauge though - new aftermarket ac compressor installed about a year ago when the bearings went out on the original - you could def hear when the bearings go out it gets very loud - its almost fall you could always get a shorter belt and bypass the compressor until you figure it out - might help from overheating in the meantime - also might tell you if its actually the compressor or not