Squealing 1st gen

[spudshaft]

I have a 91 4X4 explorer. When I first start the truck there is no sound other than the engine itself. After it begins to warm up, I am getting a squealing sound that sort of sounds like a belt slipping, but not quite. I can make the noise (almost a spinning or "whirring" sound) speed up with more gas pedal, or slow down with less. It's loud enough to be annoying.

Does this sound familiar to anybody? Bad pulley? Bad tensioner? Clutch fan? Any guesses appreciated.

 

[Sphinx]

I had same issue on my 1st gen. My belt tension pulley was squealing. From what I understand its common. Simple, and inexpensive to repair.

Just get a can of wd40 and spray the tension pulley, start the truck and see if it still makes noise. If so, turn truck off and stray fan clutch and restart engine. Do each pulley till the noise stops. If the noise stops, obviously it was the last thing you sprayed.