Serpentine Belts

The serpentine belt tensioner / pulley is on the front of the engine, and part of the belt 'routing'.

Its job is to put tension on the belt as it drives the other devices like the power steering pump, water pump, air conditioning compressor.

It is an aluminum casting that mounts with a single bolt to the engine. The pulley is attached to the arm.

There are a few ways to move / pry the arm inwards, thus releasing the tension on the belt for removing/installing: grab on the pulley bolt (15mm?) with a wrench, or some later models have an opening for a 3/8th socket wrench to attach to directly without a socket.

"Screaming"/whining that goes up and down with engine speed is a key symptom of a bearing wearing out - one of which of course is the tensioner pulley bearing.

The serpentine belt tensioner / idler pulley is preset at the factory. If it is worn out, it will need to be replaced.

NOTES:

• The belt is recommended to be replaced around 60,000 miles
• There is a wear indicator (minimum vs maximum) on the face of the tensioner arm to let you definitively now when it's time to change the belt.

• loosen the pulley bolt while it is still on the engine - it is easier this way than when the tensioner is off the engine
• loosen and remove the tensioner mounting bolt - try an 18mm socket first, it's the most common size.

You can also just replace the pulley if that is the problem and save about $25.

Price reference:

• Tensioner/pulley assembly - $40
• Pulley alone - $17-20

I just replaced the alternator on my wife's 2003 Windstar. It may not be applicable to your 97. I put the car up on ramps because the tensioner is the bottom-most pulley, nearest to the passenger compartment and almost directly below the power steering pump pulley. You need a 13mm wrench. I had a helper (my wife) working topside to put the belt over the alternator pulley, etc while I took the tension out of the tensioner pulley. I had to use the full allowable travel of the tensioner in order to get the belt on all of the pulleys properly. A younger stronger person could probably do it by himself by leaving the belt off of the balance wheel until last. There are likely spring clips that could be removed from the tensioner and then replaced as the final step, but there's not much room and my way dodged some skinned knuckles. Hope this helps.

The "official" way to release the belt tension is to rotate the tensioner about 110 degrees counter clockwise, and press a flexible metal leaf on its side into a holding slot. Doing this does away with the need to pull hard on the belt. On at least some pre-2002 Windstar models, this was rather easily done with a long screwdriver or pry bar because the tensioner and the front idler pulley were one unit. But on the 2002, Ford decided they should be 2, and moved the tension into an impossible-to-access from above location. On the 2002, you can't even get a socket on the tensioner pully bolt to rotate it that way, because there's less than 1 inch of clearance between the bolt head and the vehicle frame. You'll have to decide if it's worth getting under the vehicle to save some pulling effort.

Follow serpentine belt to pulley that is not connected to any engine component

Follow the serpentine (drive) belt into the engine compartment. Now go down. See that pulley that is farthest away from the front grill? That is the tension adjustment pulley. Put a wrench on the center bolt (on the pulley) and apply counter clockwise force. This relieves the tension on the belt. I'd recommend a friend be present to place the belt while you are holding the pulley in the retracted position. Hope this helps.

Remove the belt, and the tensioner pulley just unbolts. You will need a flat type wrench. Can be purchased at local auto store. If I remember correctly the bolt is a 15mm.

All the way in the bottom back of the belt. It's easier to access it from under the car with a 13 mm wrench. If you're replacing it jack and support the car and remove the pulley (left hand threads) from under the vehicle. Then you can easily access the 3 mounting bolts. (The pulley has to come off to completely remove the bottom mounting bolt anyway) A long tensioner wrench does not relax the pulley enough to install a new belt from the top because of the AC, etc. hoses and the limited travel of the wrench. This is how I did it for my 3.8 engine, don't know about a 3.0 liter.

pretty simple.. remove the serp belt by rotating the tensioner, then remove the bolt(s) the hold the tensioner inple. reverse to install. make a note of belt routing before you take it off, although there should be a sticker under the hood indicating belt routing.

Addendum to above:

Note that the location of the Belt Tensioner is noted incorrectly in the Ford factory service manuals. The BT is near the firewall. Loosen the bolt that holds the BT to the engine block, put a wrench on the BT pulley bolt and, using leverage, rotate the entire assembly upward to relieve the belt tension.

If the assembly is too tight to move (mine was) thread a loop of 1" webbing around the BT arm, put a crowbar through the loop and heave. Make sure to avoid punching holes through things like your AC Compressor or manifold during this process.

...and I didn't find this simple at all

Yes - the pulley can be replaced as a separate part.

When you purchase the replacement part, it should be pretty logical on how to replace it on the tensioner arm - just one nut/bolt.

One note: you may want to loosen the pulley nut/bolt while the tensioner is still mounted to the engine - AFTER the belt has been removed!

tensioner won't lose tension unless they are bad or the belt is worn out. you can't adjust the tension.

You have to take the serpentine belt off the alternator leave it on the other pulleys. Now you remove the bolt holding the tensioner. Replace the tensioner and belt. Happy Wrenching. Additonal Information from experience with this hog of a car. Pontiac decided to make this a bit of a challenge. When you get your new tensioner at the parts store, pay the deposit for free borrowing of the special long-handled wrench and shallow sockets that will allow you actually to get a tool on the tensioner bolt. Standard tools will not fit in the cramped space. When done, either keep the tool for next time, or return it for 100% refund. Note: an aftermarket tensioner will have a new bolt with it. you must use the new bolt with the new tensioner. Grandma GM's original bolt won;t fir the aftermarket tensioners.

Here's a solution to the challenge: Jack the car and take off the wheel. Take off the the plastic shrouding and the 2 clips for the hose that's in the way. Put some blocks under the motor (NOT THE OIL PAN) so that there is about a 1/2 inch of gap between the blocks and the motor. Unbolt the mounts on the passenger side so the motor drops onto the blocks. The motor should drop enough so you can get a wrench on it. I bought the serpentine wrench but only ended up really using the shallow 15mm socket on my socket wrench... tons of room!

Now Happy Wrenching! :)