Adjustment
Belt tension is not adjustable. Belt adjustment is maintained by an automatic (spring load) belt tensioner.
The belts used on these vehicle are equipped with automatic (spring load) tensioners which maintain tension. No adjustment is necessary or possible.
Belt Tension Inspection
Inspect the drive belt for signs of glazing or cracking. A glazed belt will be perfectly smooth from slippage, while a good belt will have a slight texture of fabric visible. Cracks will usually start at the inner edge of the belt and run outward. All worn or damaged drive belts should be replaced immediately.
Inspect the drive belt for signs of glazing or cracking. A glazed belt will be perfectly smooth from slippage, while a good belt will have a slight texture of fabric visible. Cracks will usually start at the inner edge of the belt and run outward. All worn or damaged drive belts should be replaced immediately.
Drive Belt Routings
The belt routing schematics are published from the latest information available at the time of publication. If anything differs between these schematics and the Belt Routing Label, use the schematics on Belt Routing Label. This label is located in the engine compartment.
Accessory serpentine belt routing-3.9L, 5.2L and 5.9L LDC gasoline engines

Fig. Accessory serpentine belt routing: Alternator (1), idler pulley (2), P/S pump (3), A/C compressor (4), crankshaft (5), belt tensioner (6) and water pump (7)-5.7L engine
Accessory serpentine belt routing-5.9L HDC and 8.0L gasoline engines with A/C
Accessory serpentine belt routing-5.9L HDC and 8.0L gasoline engines without A/C
The belt routing schematics are published from the latest information available at the time of publication. If anything differs between these schematics and the Belt Routing Label, use the schematics on Belt Routing Label. This label is located in the engine compartment.
Accessory serpentine belt routing-2001-03 5.9L Diesel engines without A/C
Accessory serpentine belt routing-2004-05 5.9L Diesel engines with A/C
Accessory serpentine belt routing-2004-05 5.9L Diesel engines without A/C

Fig. Accessory serpentine belt routing-A/C compressor (1), Without A/C (2), Power Steering Pump (3), Water Pump (4), Crankshaft Pulley (5), Auto tensioner (6), Alternator (7), Idler pulley (8)
Removal & Installation
- Attach a socket/wrench to the pulley mounting bolt of automatic tensioner.
- Rotate the tensioner assembly clockwise (as viewed from front) until tension has been relieved from belt.
- Remove the belt from idler pulley first.
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Remove the belt from vehicle.
WARNINGWhen installing the accessory drive belt, the belt must be routed correctly. If not, engine may overheat due to water pump rotating in wrong direction. The correct belt with correct length must be used.
Accessory serpentine belt routing-A/C compressor (1), Without A/C (2), Power Steering Pump (3), Water Pump (4), Crankshaft Pulley (5), Auto tensioner (6), Alternator (7), Idler pulley (8) - Position drive belt over all pulleys except idler pulley. This pulley is located between generator and A/C compressor.
- Attach a socket/wrench to pulley mounting bolt of automatic tensioner .
- Rotate socket/wrench clockwise. Place belt over idler pulley. Let the tensioner rotate back into place.
- Remove wrench. Be sure belt is properly seated on all pulleys.
- Check belt indexing marks.
Belt tension is not adjustable. Belt adjustment is maintained by an automatic (spring load) belt tensioner.
- Disconnect negative battery cable from battery.
- Rotate belt tensioner until it contacts it's stop. Remove belt, then slowly rotate the tensioner into the freearm position..
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Check condition of all pulleys.
WARNINGWhen installing the serpentine accessory drive belt, the belt MUST be routed correctly. If not, the engine may overheat due to the water pump rotating in the wrong direction.
To install:
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Install new belt. Route the belt around all pulleys except the idler pulley. Rotate the tensioner arm until it contacts it's stop position. Route the belt around the idler and slowly let the tensioner rotate into the belt. Make sure the belt is seated onto all pulleys.
Accessory serpentine belt routing-3.7L and 4.7L gasoline engines -
With the drive belt installed, inspect the belt wear indicator. On 4.7L Engines only, the gap between the tang and the housing stop (measurement A) must not exceed 24 mm (.94 inches). If the measurement exceeds this specification replace the serpentine accessory drive belt.
With the drive belt installed, inspect the belt wear indicator. On 4.7L engines, the gap between the tang and the housing stop (measurement A) must not exceed 0.94 in. (24mm)
Drive belts are equipped with a spring loaded automatic belt tensioner. This belt tensioner will be used on all belt configurations, such as with or without power steering or air conditioning. For more information, refer to Automatic Belt Tensioner, proceeding in this group.
Attach a socket/wrench to pulley mounting bolt of automatic tensioner. The threads on the pulley mounting bolt are left- hand. Relax the tension from the belt by rotating the tensioner counterclockwise (as viewed from front). When all belt tension has been relaxed, remove belt from tensioner pulley first and other pulleys last.

Fig. View of the pulley bolt (1), idler pulley (2), tensioner pulley (3), tensioner (4) and tensioner mounting bolt (5)
To install:
- Position drive belt over all pulleys except tensioner pulley.
- Attach a socket/wrench to pulley mounting bolt of automatic tensioner.
- Rotate socket/wrench counterclockwise. Install belt over tensioner pulley. Let tensioner rotate back into place. Remove wrench. Be sure belt is properly seated on all pulleys.
- Remove the air intake tube between intake manifold and air filter assembly..
- Release the belt tension by rotating the tensioner counterclockwise with a 15 mm wrench on the tensioner pulley bolt. Rotate belt tensioner until belt can be removed from pulleys.
- Remove belt.
- Gently release tensioner.
To install:

Fig. Accessory serpentine belt routing: Alternator (1), idler pulley (2), P/S pump (3), A/C compressor (4), crankshaft (5), belt tensioner (6) and water pump (7)-5.7L engine
- Position the drive belt over all pulleys except for the water pump pulley.
- Rotate tensioner counterclockwise and slip the belt over the water pump pulley.
- Gently release tensioner.
- Install the air intake tube between intake manifold and air filter assembly.
Drive belts on diesel engines are equipped with a spring loaded automatic belt tensioner. This belt tensioner will be used on all belt configurations, such as with or without air conditioning.
- Depending on the year of the vehicle, a 3 / 8 inch or 1 / 2 inch square hole is provided in the automatic belt tensioner. Attach a 3 / 8 inch or 1 / 2 inch drive-long handle ratchet to this hole.
- Rotate ratchet and tensioner assembly clockwise (as viewed from front) until tension has been relieved from belt.
- Remove belt from water pump pulley first.
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Remove belt from vehicle.
Accessory serpentine belt routing-2001-03 5.9L Diesel engines with A/C
Accessory serpentine belt routing-2001-03 5.9L Diesel engines without A/C
Accessory serpentine belt routing-2004-05 5.9L Diesel engines with A/C
Accessory serpentine belt routing-2004-05 5.9L Diesel engines without A/C
To install:
- Attach a 1/2 inch ratchet to tensioner.
- Rotate ratchet and belt tensioner clockwise. Place belt over water pump pulley. Let tensioner rotate back into place. Remove ratchet. Be sure belt is properly seated on all pulleys.
- Drive belts on these engines are equipped with a spring loaded automatic belt tensioner. This belt tensioner will be used on all belt configurations, such as with or without power steering or air conditioning.
- Attach a socket/wrench to pulley mounting bolt of automatic tensioner.
- Rotate tensioner assembly clockwise (as viewed from front) until tension has been relieved from belt.
- Remove belt from idler pulley first.
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Remove belt from vehicle.
View of the idler pulley (1), tensioner (2) and fan blade (3)
To install:
- Position drive belt over all pulleys except idler pulley. This pulley is located between generator and A/C compressor.
- Attach a socket/wrench to pulley mounting bolt of automatic tensioner .
- Rotate socket/wrench clockwise. Place belt over idler pulley. Let tensioner rotate back into place. Remove wrench. Be sure belt is properly seated on all pulleys.
- Check belt indexing marks.