My 5.0 Ranger has accessory drive of unknown vintage. Idler pulley is old style smooth with flange and is making noise. All I can find locally is smooth without flange. Identical dimensions. Can I run it? Every other vehicle I have owned used the no flange variety. Thanks!

 

Yes, should be fine, if idler belt distance isn't too far from adjacent pulleys

The flange is used to keep belt from drifting side to side which can cause it pop off or wear out