For decades, drive belts, V-belts, multi-vee-belts, and serpentine belts have been used to transmit power from the engine crankshaft pulley to add-ons, like the power steering pump, air conditioning compressor, water pump, or cooling fans. Toothed timing belts and timing chains, too, are used to transmit power from the crankshaft to the camshafts, plus some from the camshaft to camshaft, depending on engine design.
The drive belt, timing belt, or timing chain will not work very well, or for very long, if, with incorrect tension. A loose drive belt won’t drive the item reliably, slipping and making sound. Conversely, an excessively limited belt may cause accessory or pulley bearing harm. Various kinds of tensioner pulley keep long-term engine and item quietness and reliability.
Tightening or Loosening
Sometimes, maintenance or repair will require tightening or loosening a tensioner pulley. Replacing a drive belt or timing belt, for instance, would need you to loosen a tensioner pulley to make room for the brand new belt, as the brand new belt is smaller sized than the worn drive belt.
You’ll need to tighten a tensioner pulley, in most cases, after the installing a new drive belt, or even to change for a stretched drive belt that hasn’t worn enough to warrant replacement. Extend belts don’t require tensioner pulleys but are “stretched” into place utilizing a special tool-always utilize the special tool to prevent belt damage.
Tensioner pulleys generally fall into two classes: accessory-integrated (AI) and non-accessory-integrated (NAI). Think of AI tensioners as adjustable components, such as for example an alternator, and NAI tensioners as adjustable idler pulleys. There are three types of tensioner pulleys and several ways to loosen them.
Mechanical tensioner pulleys will be the Car Pulley Belt simplest, the majority of common, and least prone to failure. There is definitely one caveat, nevertheless, as mechanical tensioner pulleys require manual adjustment. This makes them prone to user 
error, resulting in insufficient or excessive belt stress. Additionally, they have to be adjusted to compensate for belt stretch as time passes.