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

Toyota and other timing belt tensioners are loosened simply by removing them from the engine. You must 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 vehicles with timing chains, though some are used in combination with timing belts. Hydraulic tensioners are driven by oil pressure from the engine essential oil pump and may press on a tensioner pulley (timing belts) or pressure slipper (timing chain). You will likely need the entire year, make, and model info, 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. Take away 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 maintains drive belts from slipping and producing noise. To loosen a drive belt springtime tensioner pulley, refer initial to the restoration manual or owners manual’s specific yr, make, and model info.
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 correct tool, release pressure on the belt. You will have to hold some springtime tensioners while slipping on a new belt. Others may have a locking mechanism, such as a hole for a locking pin or hex important.

To loosen an NAI tensioner, loosen the locking nut or bolt, after that cool off the tensioner screw. Press the pulley toward the other pulleys or add-ons, loosening the belt.
Spring tensioner pulleys, because the name implies, use a spring to hold tension upon the belt. Most, if not all, spring tensioner pulleys are NAI tensioners you need to include a hydraulic damper. They are more technical and costly but don’t require adjustments and are less prone to user error.