How do I tighten a serpentine belt on my 94 expo

I think they are under the bonnet on these follow the fuel lines back from the engine

3.1L Engines - 1998-93 VEHICLES
(see Figures 5, 6, 7 and 8)

1. Disconnect the negative battery cable.
2. If necessary for access to the alternator, remove the air cleaner assembly.
3. Remove the serpentine belt
4. Label and detach the electrical connector(s) from the back of the alternator.

Fig. 5: After removing the serpentine belt, detach the electrical connector from the rear of the alternator

1. Remove the rear and front attaching bolts, and unfasten the brace-to-alternator bolt.

Fig. 6: Unfasten the front and rear mounting bolts...

Fig. 7: ... then remove the brace-to-alternator bolt

1. Carefully remove the alternator assembly, making sure all wires are disconnected.
   

If the alternator brace is removed, the studs must be retightened before installation or damage to the brace may result.

Fig. 8: Alternator (generator) removal and installation - 1992 3.1L engine shown (click image for zoom)

To install:

1. Position the alternator into the mounting bracket.
2. If necessary, attach the battery positive lead and nut to the alternator output terminal. Tighten to 71 inch lbs. (8 Nm).
3. Install the brace-to-alternator bolt, but do not tighten at this time.
4. Install the front and rear mounting bolts. Tighten the bolts as follows:
   1. Long bolt to 35 ft. lbs. (47 Nm)
   2. Short bolt to 18 ft. lbs. (25 Nm)
   3. Bracket bolt to 18 ft. lbs. (25 Nm)
5. Check that tightening of the brace bolts did not bind the alternator.
6. Attach the electrical connector(s).
7. Install the serpentine belt
8. If removed, install the air cleaner.
9. Connect the negative battery cable.

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1989–92 VEHICLES

1. Disconnect the negative battery cable.
2. Remove the serpentine belt and timing belt cover.
3. Loosen the water pump bolts and release tension with tool J–33039 or equivalent.
4. Raise and support the vehicle safely.
5. Remove the crankshaft pulley.
6. Carefully lower the vehicle, then remove the timing belt. Fig. 11: Exploded view of the timing belt assembly — 1989–92 OHC engines
   To install:
   
7. Turn the crankshaft and the camshaft gears clockwise to align the timing marks on the gears with the timing marks on the rear cover.
8. Install the timing belt, making sure the portion between the camshaft gear and crankcase gear is in tension.
9. Using tool J–33039 or equivalent, turn the water pump eccentric clockwise until the tensioner contacts the high torque stop. Tighten the water pump screws slightly.
10. Turn the engine by the crankshaft gear bolt 720°to fully seat the belt into the gear teeth.
11. Turn the water pump eccentric counterclockwise until the hole in the tensioner arm is aligned with the hole in the base.
12. Tighten the water pump screws to 18 ft. lbs. (24 Nm), while checking that the tensioner holes remain as adjusted in the prior step.
13. Install the crankshaft pulley, timing belt cover and the serpentine drive belt.

1993–94 VEHICLES

1. Disconnect the negative battery cable, then partially drain and recover the cooling system.
2. Remove the coolant recovery reservoir.
3. If equipped, remove the A/C belt.
4. Remove the serpentine belt.
5. Disconnect the evaporative emission pipe assembly.
6. Remove the crankshaft pulley assembly.
7. As outlined earlier, remove the timing belt front cover.
8. Align the marks on the crankshaft sprocket with the marks on the rear timing belt cover by rotating the crankshaft.
9. Loosen the water pump retaining bolts, and release the tension with tool J 33039-A or equivalent.
10. Carefully lower the vehicle, then remove the timing belt. Fig. 12: Timing belt installation and tightening specifications — 1993–94 2.0L OHC engines
    To install:
    
11. Turn the crankshaft and camshaft gears clockwise to align the timing marks on the gears with the timing marks on the rear cover.
12. Install the timing belt, making sure that the portion between the camshaft gear and crankshaft gear is in tension.
13. Using tool J 33039-A, or equivalent adjustment tool, turn the coolant pump eccentric clockwise until the tensioner arm contacts the high torque stop. Tighten the water pump screws slightly.
14. Turn the engine by the crankshaft gear bolt 720°clockwise to fully seat the belt into the gear teeth.
15. Turn the coolant pump eccentric counter clockwise until the hole in the tensioner arm is aligned with the hole in the base. This must be done with the engine at room temperature, approximately 68°F (20°C).
16. Tighten the water pump screws while checking that the tensioner holes remain as adjusted as in step 15.
17. As outlined earlier, install the timing belt cover.
18. Install the crankshaft pulley.
19. Connect the evaporative emission pipe assembly.
20. Install the serpentine drive belt and the A/C belt (if equipped).
21. Install the coolant recovery reservoir.
22. Properly fill the cooling system, then connect the negative battery cable.

if you are talking about the serpentine belt which drives the alternator / water pump etc, it may be falling off if it is miss-routed or if any of the pulleys are out of alignment or if the belt tensionr is not properly tightened, the tensioner is the pulley which bears on the outside of the belt (smooth side) this pulley may be gummed up and give you the impression it doesnt move clean it up loosen it off

the belt that drives the water pump also drives the power stearing pump and it was locked up and not allowing it to spin fast enough for it to work or the belt broke

For a 94 Jeep grand cherokee, the tension is controlled through a long bolt on the power steering bracket. The bolt is about 6 inches long, located underneath the power steering on the driver side. Lossen the lockbolt holding it in place, as well as the Power steering attach bolts, and turn the long bolt to tighten/loosen. I believe these are all 13 mm bolts.

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here is step by step instruction on how to replace you alternator. please do not forget to rate and comment abotu your experience with fixya today 3.8L (VIN 1) Supercharged Engines

1. Disconnect the negative battery cable.
   
2. Remove the serpentine drive belt from the alternator, as outlined in Section 1 of this manual.
   
3. Detach the electrical connections from the alternator.
   
4. Unfasten the alternator mounting bolt and mounting bolt and nut.
   
5. Remove the alternator from the vehicle.
   To install:
   
   1. Position the alternator in the vehicle and secure with the mounting nut and bolt. Tighten to 5 ft. lbs. (8 Nm).
      
   2. Install the remaining mounting bolt and tighten to 5 ft. lbs. (8 Nm).
      
   3. Attach the alternator connections. Tighten the output terminal nut to 66 inch lbs. (7.5 Nm).
      
   4. Install the serpentine drive belt.
      
   5. Connect the negative battery cable.
      

3.8L (VIN 3, C & L) Engines

1. Disconnect the negative battery cable.
   
2. Using a suitable breaker bar or ratchet, rotate the tensioner counterclockwise, then remove the serpentine drive belt. For more information regarding serpentine drive belt removal, please refer to Section 1 of this manual.
   
3. If necessary, remove the fuel rail cover.
   
4. While supporting the alternator, remove the mounting bolts.
   
5. Tilt the alternator forward, then label and detach the electrical connectors.
   
6. Remove the alternator from the vehicle.
   
7. To install:
   
   1. Support the alternator in position, then install the alternator.
      
   2. Install the mounting bolts and tighten to 1 ft. lbs. (11 Nm).
      
   3. Attach the electrical connectors at the back of the alternator. Tighten the alternator output terminal nut to 93 inch lbs. (10.5 Nm) for 1987-92 vehicles, or to 66 inch lbs. (7.5 Nm) for 1993-94 vehicles.
      
   4. If removed, install the fuel rail cover.
      
   5. Install the serpentine drive belt and rotate the tensioner into position.
      
   6. Connect the negative battery cable.
      

Fig. Fig. 8 Accessory serpentine belt routing-7.3L turbo diesel engine

if the belt is loose you might have the wrong belt installed on, or the serpentine belt tensioner must to be replaced, they adjust automatic, with spring loaded belt tensioner
and i will apreciate the ranking to my answer thanx