I also have a 91 and can tell you that the roar from the fan is quite normal. In fact, if you do not hear it , then the clutch is to the point where cooling will be a problem on those extreemely hot days when idleing in traffic with the A/C on. I started to have cooling problems and changed everything imaginable, but nothing fixed it till I changed the fan clutch and got the familiar roar back I had when vehicle was new.
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