For many years, drive belts, V-belts, multi-vee-belts, and serpentine belts have already been used to transmit power from the engine crankshaft pulley to accessories, such as the power steering pump, air-con compressor, water pump, or Car Pulley Belt 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 well, or for very long, if at all, with incorrect tension. A loose drive belt won’t drive the accessory reliably, slipping and producing sound. Conversely, an excessively restricted belt may cause item or pulley bearing damage. Various kinds of tensioner pulley maintain long-term engine and accessory 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 require you to loosen a tensioner pulley to create room for the brand new belt, as the brand new belt is smaller sized than the worn drive belt.

You will have to tighten a tensioner pulley, in most cases, after the installing a fresh drive belt, or to change for a stretched drive belt that hasn’t worn enough to warrant replacement. Stretch out belts don’t need tensioner pulleys but are “stretched” into place using a special tool-always utilize the special tool to avoid belt damage.

Tensioner pulleys generally fall into two types: accessory-integrated (AI) and non-accessory-integrated (NAI). Think of AI tensioners as adjustable accessories, such as for example an alternator, and NAI tensioners as adjustable idler pulleys. There are three types of tensioner pulleys and many methods to loosen them.
Mechanical tensioner pulleys will be the simplest, most common, and least prone to failure. There is one caveat, nevertheless, as mechanical tensioner pulleys need manual adjustment. This makes them susceptible to user error, leading to insufficient or extreme belt tension. Additionally, they need to be adjusted to pay for belt stretch over time.