I have a 91 Explorer with a 4.0L V6. The engine fan makes a lot of noise, it "roars". I have a 93 Ranger with a 4.0L V6 that does not "roar".

I have replaced the fan clutch on the Explorer with the HD unit specified for the Explorer with AC and Auto. The noise was even worse! I replaced the fan clutch with the lighter duty clutch specified for vehicles without AC which is the same unit specified for my 93 Ranger (with AC). It still makes noise. The Ranger is almost silent. I have examined the fan from the Explorer for damage and found none.

Is there some difference in the fans? Should I get a fan off a scrapyard Ranger and put it on the Explorer? The fan clutch on my Ranger is in fine shape, the engine runs cool even with AC. Is there a difference in the fan shroud?

Any help is appreciated :-)