Next time you work with a drive belt, timing belt, or timing chain, you’ll likely need to loosen a tensioner pulley to eliminate it. Subsequent these general Car Pulley Belt recommendations and specific instructions from your own owners manual or repair manual, your belt or chain will function for the life span of your car.

Toyota and various other timing belt tensioners are loosened simply by removing them from the engine. You need to slowly compress them in a bench vice and lock them with a pull-pin before reinstallation.
Hydraulic (not hydraulic-damped) tensioners are nearly always located in the timing case, mostly upon automobiles with timing chains, while some are used in combination with timing belts. Hydraulic tensioners are driven by essential oil pressure from the engine essential oil pump and may press on a tensioner pulley (timing belts) or stress slipper (timing chain). You will likely need the year, make, and model information, and you may need to use special tools for this type of tensioner pulley.
Typically, a hydraulic tensioner must be “reset” and locked after removing it from the engine. Remove the lock only following the tensioner, pulley, or slipper, and timing belt or timing chain are installed and aligned.

The spring maintains tension, as the hydraulic damper keeps it from bouncing under load changes. This prevents timing belts and timing chains slapping and jumping the teeth and will keep drive belts from slipping and producing noise. To loosen a drive belt springtime tensioner pulley, refer initial to the repair manual or owners manual’s specific 12 months, make, and model details.
You may need a special tool, but many spring tensioners have a square hole, for a 3/8” or 1/2” breaker bar, or a hex or square protrusion for a wrench or socket. Using the appropriate tool, release stress on the belt. You’ll need to hold some springtime tensioners while slipping on a new belt. Others may have a locking mechanism, like a hole for a locking pin or hex essential.

To loosen an NAI tensioner, loosen the locking nut or bolt, after that back off the tensioner screw. Press the pulley toward the additional pulleys or add-ons, loosening the belt.
Spring tensioner pulleys, since the name implies, make use of a springtime to hold tension upon the belt. Most, if not absolutely all, springtime tensioner pulleys are NAI tensioners and include a hydraulic damper. They are more technical and expensive but don’t require modifications and are less prone to user error.