The next time you utilize a drive belt, timing belt, or timing chain, you’ll likely need to loosen a tensioner pulley to eliminate it. Following these general guidelines and specific instructions from your own owners manual or repair manual, your belt or chain will function for the life of your car.

Toyota and various other timing belt tensioners are loosened by simply 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 situated in the timing case, mostly on vehicles with timing chains, though some are used in combination with timing belts. Hydraulic tensioners are driven by oil pressure from the engine 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 Car Pulley Belt prevents timing belts and timing chains slapping and jumping the teeth and retains drive belts from slipping and making 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 pressure on the belt. You’ll need 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 key.

To loosen an NAI tensioner, loosen the locking nut or bolt, after that back off the tensioner screw. Force the pulley toward the other pulleys or accessories, loosening the belt.
Spring tensioner pulleys, as the name implies, use a springtime to hold tension upon the belt. Most, if not absolutely all, springtime tensioner pulleys are NAI tensioners you need to include a hydraulic damper. They are more technical and expensive but don’t require adjustments and are less prone to user error.