ldle in english means to sit at rest or be still so i can see where this term may confuse you. but an idler pulley on a car rides on a bearing that spins. so YES
it turns. it is used as an adjustment that your fan or SERPENTINE belt rides on .
to keep tension on your belt.
to clarify, the pulley by itself will not turn, it is turned by the motion of the belt
moveing on in.
Idler pulleys are used to maximize belt contact with other pulleys and to redirect belt around other parts that might interfere with the belt.
They very in price, depending on the car, from around $12 to $80.
there is one, but two if you count your belt tensoiner.
only if the idler arm will not hold the tension on the belt and the pulley needs replaced when the are warn sharp or warn flat
The engine usually has an idler and/or tensioning pulley as well as a few pulleys that use the power of a traveling serpentine belt to drive components such as the alternator, a/c pump, etc. Any of the pulleys that have one or more grooves that assist to guide the belt(s) are, technically, sheaves. Idler or tensioner pulleys that are completely flat because the flat back of the belt rides on them are not sheaves, but are pulleys.
== == it is a free pulley that works as a tensioner on any belt bolted to hold or spring loaded An idler pulley usually tensions a belt.. eg supercharger belt is kept taut by its respective idler pulley
An accessory or idler pulley is frozen or in very bad shape and is snapping the tensioner and bolt from all the torque being applied to it. Check all your pulleys when you have it off. They should rotate freely.
Put an 18mm wrench on the lower tensioner belt and rotate CCW to loosen the tension. Remove the belt from around the alternator pulley, and slowly release the tensioner. Unwrap the belt from all the pulleys and install the new belt following the belt diagram located near the radiator support. ALWAYS make sure the grooved side of the belt is contacting the grooved pulleys, and the smooth side of the belt is contacting the smooth pulleys (Idler pulleys). Groove to Groove -- Smooth to Smooth
Take it to the dealer! It's not a job for the timid or any shop that doesn't know what they are doing. Make sure you get the idler pulleys and automatic tensioner replace along with the timing belt. If the bearings seize in those idler pulleys it will ruin the belt and in turn take out your engine.
The idler pulley is on a spring loaded arm. To release the tension, use a long breaker bar, or a long pipe on a box wrench. Use the proper size wrench or socket, and put it on the idler pulley bolt head. Rotate the idler arm assembly in a counter clock-wise direction and the tension will be released. Then you can remove the belt. Hint use rubber bands to keep the belt on the other pulleys while replacing the alternator. Joedi
take pressure off the belt by pulling back the spring tensioner. Remove old belt, put the new belt on all the pulleys but the idler pulley, pull the tensioner back slip belt on to idler, Look to make sure you have the belt on all pulleys good, your done.
In automotive terms, There are drive pulleys such as the drive pulley mounted to the crankshaft on most engines. There are driven pulleys such as an alternator, power steering, water pump, a/c compressor and all the accessories driven by the drive pulley. There are idler pulleys and tensioner pulleys. There are timing belt pulleys. And for non automotive related terms, There are block and tackle pulley systems. There are pulley hoists. Wire rope pulley blocks. Cable pulleys. Rope pulleys.