How Do I Release The Tension Pulley To Change A Serpentine Belt On A 2000 Mercury Mountaineer? What type of tool whould I use. I need to take off the belt so I can swap out the altenator.

Hi:

First, you want to make a drawing of the belt routing, if there isn't a picture of how it goes on a decal, under the hood.
The tensioner pulley is released in one of two ways, depending on the type installed.

It either has a square hole you can insert a ratchet or breaker bar into, and rotate it while slipping the belt off, or some have a hex head area that you can use a socket or wrench to rotate it. They are usually spring loaded, so to put the belt back on, you route the belt around everything else, then rotate down the tensioner, and put the belt over it last.

Hello there:
on the tension idler pulley look real closley and you will see a square slot
on it this is for a rachet wrench with a extension on it simpley insert it in the hole and push lt as if you were tightening a bolt and you will see the pulley start to move it takes a good amount of pressure to get the pulley to move and hold once it is loose so be carefull If you have a cheater bar that you can slide over the rachet wrench this will help you move the pulley a lot easier ok hop that this has been very helpfull
best regardds michael