Next time you utilize a drive belt, timing belt, or timing chain, you’ll likely have to loosen a tensioner pulley to remove it. Subsequent these general suggestions and specific instructions from your own owners manual or restoration manual, your belt or chain will function for the life of your car.

Toyota and additional 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 positioned in the timing case, mostly on automobiles with timing chains, though some are used in combination with timing belts. Hydraulic tensioners are powered by essential oil pressure from the engine oil pump and may press on a tensioner pulley (timing belts) or tension slipper (timing chain). You will likely need the year, make, and model details, and you may have to use special equipment for this sort 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 teeth and continues drive belts from slipping and making noise. To loosen a drive belt spring tensioner pulley, refer 1st to the repair manual or owners manual’s specific season, make, and model info.
You might 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 stress on the belt. You will have to hold some spring tensioners while slipping on a fresh belt. Others may possess 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. Push the pulley toward the additional pulleys or components, loosening the belt.
Spring tensioner pulleys, since the name implies, make use of a spring to hold tension on the belt. Most, if not absolutely all, springtime tensioner pulleys are NAI tensioners and include a hydraulic damper. They are more technical and costly but don’t require adjustments and are less susceptible to user error.