Took the 98 Ranger(only 52K) for along trip from NJ to NC to give to my son for a temp ride and several times in front of the engine something would kick in and produce a constant steady whine/howl that was louder than anything else under the hood.Was a little disturbing to hear while idling . Seemed to happen after it was running for a while, first time after about 1/2 hr then later again on the ride home after a few hrs on the road. Couldnt figure excactly where it came from, steering pump/compressor area? It stayed on most of the ride home( hrs) but didnt seem to affect anything like temp, rpm's. oil pressure, steering. It was very hot out but dont know if that was a cause. Was definatly anxious about getting home ok but nothing happened. As a side note I was afraid to use the AC just in case but after a few HOT hrs driving in stalled Wash DC traffic I decided to put just the fan on and it blew cold air thru the defroster and a little thru the floor no matter that the AC was not on or whatever air control s I tried so I enjoyed it anyway. Confused? I am. Any ideas? Also I dont drive it too much so I'm not intimately familiar with everything in the Ranger and typically dont use the Ac anyway, prefer open windows and fresh air!

 

Most likely it was the fan clutch kicking in and speeding up the engine fan. That would cause the howl noise. Did the noise go away after you drove at highway speeds for a few miles?

 

not sure but I think it was there all the time, I know when I pulled in to get gas it was still racing away at idle while waiting for the pump.