Next time you work with a drive belt, timing belt, or timing chain, you’ll likely have to loosen a Car Pulley Belt tensioner pulley to eliminate it. Following these general guidelines and specific guidelines from your own owners manual or restoration 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 gradually compress them in a bench vice and lock them with a pull-pin before reinstallation.
Hydraulic (not hydraulic-damped) tensioners are nearly always positioned in the timing case, mostly on automobiles with timing chains, though some are used in combination with timing belts. Hydraulic tensioners are driven by essential oil pressure from the engine essential oil pump and could press on a tensioner pulley (timing belts) or stress slipper (timing chain). You’ll likely need the entire year, make, and model details, and you may need to use special tools for this kind of tensioner pulley.
Typically, a hydraulic tensioner must be “reset” and locked after removing it from the engine. Take away the lock only after the tensioner, pulley, or slipper, and timing belt or timing chain are set up 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 sound. To loosen a drive belt springtime tensioner pulley, refer first to the restoration manual or owners manual’s specific calendar year, 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 will have to hold some spring tensioners while slipping on a fresh 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 cool off the tensioner screw. Drive the pulley toward the additional pulleys or add-ons, loosening the belt.
Spring tensioner pulleys, since the name implies, make use of a spring to hold tension on the belt. Most, if not all, springtime tensioner pulleys are NAI tensioners you need to include a hydraulic damper. They are more technical and expensive but don’t require modifications and are less susceptible to user error.