An idler pulley is a pulley that does not drive and is not connected to any device that is driven. It serves to either tension a belt or to route a belt to clear an obstacle.
Most technicians refer to the idler pully for the timing belt as just idler.
first you should release the belt tension pully and remove the belt. Then the idler pully has a bolt through the center remove the bolt and the pully should come off.
Unbolt, slide off. Slide on new part, bolt back on.
Pin the top tension idler pully..take the front wheel off...the bottom idler pully is on an excentric...loosen same....belt goes slack.... put new belt on,set the excentric as tight as possible.. remove the pin in the top tension idler pully belt should be tight after doing this... happy days
the idler pully is the top center that that spins freely and is connected to the block.
idler pulley, the only one that will move
Find the idler pully of the serpentine belt system. It is usually the one that appears to not "drive" any system and is normally located towards the top of the other pullys. On the idler pully assembly, you will find a bolt (not the bolt in center of pully or the one at the pivot point of assembly). Using the correct sized socket and a large ratchet (or wrench) as a lever, pull or push the idler pully assembly, which is spring tensioned, until the pully moves in far enough to get new belt on. Slowly release tension until belt is tight against the idler pully under the assembly's spring tension. Be sure belt is properly seated on all pullys without any twists.
Idler pully.
It is called an Idler pully and is not there to tension the belt.
Most idler pulley's are near the top and usually quite easy to get to. Press on the belt somewhere, enough to deflect it a couple inches and watch to see which pully is mounted on a tension spring. That is the idler pulley.
Damage, play/wobble, squealing while in operation.
It's a left hand thread. Crank to the right.