What is the procedure for replacing/tightening the serpentine belt on A 2003 4cyl Vue AWD? Is the 90 degree twist test indicate appropriate tightness?

fel_pro_torque_specs_guide.pdf

Most newer vehicles have a spring loaded belt tensioner that requires no setting. Year/make/model?? If it is an adjustable belt, there is a tension gauge that correctly sets the tension. Without the gauge,rule of thumb is to tighten the belt until you can only turn it 90 degrees at the midway point from 2 pulleys.

How do you know it's only putting out about 1/2 ? an 1/2 what ? Amps or volts ? Did you hook up a volt meter to the battery posts ? red to red an black lead to negative post of the battery ? Does it show 13.1 to 14. 1 volts with the engine running , if so it's charging . The only thing that would cause the alternator not to put out full charge amps would be a bad diode inside the alternator or a power or ground issue. You need to check power an grounds doing a voltage drop test . Voltage Drop Testing the Charging System

More then likely your belts have worn and need tightening. When my screech, almost every time it's the alternator belt. Easy to do, BUT a little time consuming. Not only do you have to loosen the bolt at the top near where the adjusting bolt is, but the one underneath that it pivots on. You should just barely be able to twist the belt 90 degrees when tightened. Too tight and you'll damage the bearings in the water pump.

1) Open driver's door window (in case the car auto-locks shut), remove keys from car's interior, and disconnect the vehicle's battery's negative terminal wire and tuck it away, making sure it cannot touch the battery negative terminal (you might wrap it in a cloth, just to make absolutely sure) (make sure you have any stereo security codes, before disconnecting this). Also make sure you have any alarm system turned off, or have the key to do so.


2) Remove the alternator drive belt. Serpentine belt types require a spring tensioned pulley to be forced against spring pressure, away from the belt in order to remove the belt (MAKE SURE you take careful note of this belt's route for easy refit. Take a photo if necessary!). Traditional tensioners require a locking bolt to be slackened and then an adjustment bolt to be slackened, plus affixing bolt to be slackened in order to freely remove the belt.
3) Disconnect the wires from the back of the alternator unit. You may typically have one plug connector and one or two heavy duty wires on the back.


4) Remove any remaining alternator fixing bolts which are keeping it affixed to the engine block, and remove alternator.


Refit:


1) Locate alternator position and lightly screw in all affixing bolts (do not tighten if using traditional type, manual tensioner). Tighten if using a serpentine belt tensioner (spring loaded type).


2) Re-attach all wiring and check for tight connections.


3) Replace drive belt. If using traditional tensioner, then manually adjust the belt tension so that you can twist the belt to about 90 degrees when tight, no further.


4) Clear the engine bay of all tools, reconnect vehicle battery negative lead.


5) Restart vehicle.


6) Listen for belt squeal (may need tightening further if manually adjusted). Take note of dashboard charge warning indicator. If illuminated, then check battery connections and alternator connections.


7) If you have a multimeter, then check voltage across battery terminals with vehicle running. Voltage should measure around 14Volts with a healthy alternator fitted.


8) After running for a few minutes, stop engine and recheck belt tension if using a manual tensioner. BE CAREFUL of any hot areas as these may burn. If in doubt, then wait until the engine is cold and re-adjust if necessary.


Job Done!


Good luck!

1. 1 Check to ensure the Sienna's engine is cold, then make sure the Sienna is in park, the ignition is in the off position and the key is removed from the ignition to prevent any possibility of the engine engaging during the serpentine belt replacement.
   
2. 2 Open the hood and locate the serpentine belt routing diagram sticker on the side of the engine casing. Study it for a moment before removing the existing belt. It is essential the new belt be installed exactly as the diagram indicates.
   
3. 3 Find the tensioner pulley, the main pulley that controls the serpentine belt, and fit a 1/2-inch socket wrench over the self-tensioner on the outside of the pulley.
   
4. 4 Pull the wrench to the left to move the pulley forward, which loosens the belt, then remove the belt.
   
5. 5 Compare the old serpentine belt with the new, replacement belt for length, width and number of grooves on the belt's underside. Be certain the replacement belt is the right part.
   
6. 6 Fit the new belt on to each pulley according to the serpentine belt routing diagram on the manufacturer's sticker, or according to the drawing made prior to removing the old belt. Fit the new belt on to the tensioner pulley last, again applying pressure on the pulley's self-tensioner with the half-inch socket wrench to loosen the pulley.
   
7. 7 Release the pressure on the self tensioner and allow the tensioner pulley to ease back into place, thereby tightening the new serpentine belt with the appropriate tension.
   
8. 8 Remove the wrench and close the hood.
   

Thank you and good luck,
Lee

Maybe one of the drive pulleys has become seized. Sometimes the air conditioning compressor can be become seized and this puts a lot of strain on the serpentine belt. Did you take the tension of the tensioner pulley to slip the belt on or did you force it on. If you put it on with brute force the chances are that you did real damage to the belt. Check that all the pulleys turn (by hand). Check out how to take the tension off the tensioner pulley (often it is just a matter of putting a spanner on the pulley's central nut and rotating the mechanism anticlockwise against the spring tension. The belt should slip on without any effort if the tensioner is held back. Once on the tensioner can be released. The tension on the belt should be enough so that it is difficult to twist the belt, between pulleys, beyond about 90 degrees.

how do I loosen tension for serpentine belt

Is it worse when cold or wet? Could be a lose or worn serpentine belt, or a bad tensioner.
Check belts for any cracks on it (check both sides, inside normally cracks first)
Check tension of the belt, with your fingers you should be able to twist the best roughly 45 degrees, if it's a lot more than that check the tensioner, try tightening the bolt to add tension.

Belt is getting hot, because it might be loose or one of the components (AC, water pump, alternator etc) has trouble with rotation (getting stuck). In most common case it is alternator.
If you are handy with that you need to remove the belt and rotate the alternator, water pump, ac pulleys and see which one has problem with rotation. Also you can check for free at Autozone if alternator giving enough charge.

Libricants are prohibited to use, belt will be slippering and wont rotate the pulleys for AC, water pump, alternator.

For tension serpentine belt can be checked by twisting it, it should not twist more then 90 degree, or by pushing, no more the 1/4 inch freedom then you push it
Good Luck