Engine Belt Tensioner

When changing the fan belt tensioner on any engine there are a few things to keep in mind. The belt will usually need to be replaced, if the tensioner is bad. This is because the old one probably was thrown off the engine or has been squealing. Throwing the belt off the engine creases the belt, and it will want to jump off all the time after that. Squealing belts actually get glazed or burned, and once they start making noise, they never stop doing it. If your belt had been squealing, it might be a good idea to also clean the pulleys with a scotch-brite pad while it is off. This will make sure that the new belt has a nice clean surface to ride on, and the new tensioner will have less to worry about as it gets jerked around pretty hard as the engine pulses through its revolutions. Make sure you have a socket set, and some belt tensioners even have 'Torx' head screws holding them on (3.0L Ford V6).

Anyways, you are certain you have the right tools for the job and you know the way the belt was routed on the engine. If you do not know, or the diagram is missing from the under hood sticker on your vehicle, you can get a print out of the routing from the auto parts store, when you pick up the parts. Anyways, now you are to the point of changing the tesioner, the belt is off and the pulleys are clean, now you need to unbolt the bolt through the middle of where the tensioner pivots. If there is no bolt there, then it is under a 'cover' that you will need to pop loose with a screwdriver

Once you have the bolt out, the tensioner assembly will come right off with it. IF the engine is dirty, it will want to stay in place with the tab in the back that holds it straight and from twisting. If it does this, simply give it a tap and it will come loose. Make sure to clean all surfaces when you take it apart. Now it is time to put the new tensioner on the engine.

When you look at the back of the tensioner, you will notice a little 'tab'. That tab goes into a hole in the engine to stop it from rotating, and coming loose. Put the tensioner to the engine and tighten the bolt. It should be pretty tight, usually close to 30 ft/lb, but the repair manual should be consulted, if you are concerned with this. The Auto parts store might even be able to tell you the torque specification, on the accessory belt tensioner bolt. The main point here, is to make sure it m mounts flush to the engine, and is not 'in a bind' anywhere. Once you are happy with the bolt, and tensioner mounted to the engine securely, and properly, replace the 'dust cover' that may have been covering the bolt.

So you have changed the tensioner, and now you only need to put the belt back on the engine. I can offer the advice of being sure to start at the bottom, and work your way to the top. When you get to the last pulley, you should be able to have enough leverage to pull on the tensioner, and slip the belt over the last pulley. I usually make this one the alternator, since they are so easy to get to.