Dodge Durango (HB). Manual - part 131

Correct drive belt tension is required to ensure opti-
mum performance of the belt driven engine accesso-
ries. If specified tension is not maintained, belt
slippage may cause; engine overheating, lack of
power steering assist, loss of air conditioning capacity,
reduced generator output rate, and greatly reduced
belt life.

It is not necessary to adjust belt tension on the 3/7L/
4.7L or 5.7L engines. These engines are equipped
with an automatic belt tensioner (1). The tensioner
maintains correct belt tension at all times. Due to use
of this belt tensioner, do not attempt to use a belt ten-
sion gauge on these engines.

OPERATION

The automatic belt tensioner maintains belt tension by using internal spring pressure, a pivoting arm and pulley to
press against the drive belt.

REMOVAL

3.7L/4.7L ENGINE

On 4.7L engines, the tensioner (3) is equipped with
an indexing tang on back of tensioner and an
indexing stop on tensioner housing. If a new belt
is being installed, tang must be within approxi-
mately 24 mm (.94 inches) of indexing stop. Belt is
considered new if it has been used 15 minutes or
less.

If the above specification cannot be met, check for:

•

The

wrong

belt

being

installed

(incorrect

length/width)

•

Worn bearings on an engine accessory (A/C
compressor,

power

steering

pump,

water

pump, idler pulley or generator)

•

A pulley on an engine accessory being loose

•

Misalignment of an engine accessory

•

Belt incorrectly routed.

Note: A used belt should be replaced if tensioner
indexing arrow has moved to the minmum tension
indicator. Tensioner travel stops at this point.

1. Remove accessory drive belt (Refer to 7 - COOL-

ING/ACCESSORY

DRIVE/DRIVE

BELTS

REMOVAL).

ACCESSORY DRIVE

7 - 19

2. Remove tensioner assembly from mounting bracket

(1).

WARNING: BECAUSE OF HIGH SPRING PRES-
SURE,

NOT

ATTEMPT

DISASSEMBLE

AUTOMATIC TENSIONER. UNIT IS SERVICED AS
AN ASSEMBLY EXCEPT FOR PULLEY ON TEN-
SIONER.

3. Remove pulley bolt. Remove pulley from tensioner.

5.7L ENGINE

1. Remove accessory drive belt (Refer to 7 - COOL-

ING/ACCESSORY

DRIVE/DRIVE

BELTS

REMOVAL).

2. Remove tensioner and mounting bracket.

3. Remove the tensioner assembly from the mounting

bracket.

INSTALLATION

3.7L/4.7L ENGINE

1. Install pulley and pulley bolt to tensioner. Tighten bolt to 61 N·m (45 ft. lbs.) torque.

2. An indexing slot is located on back of tensioner. Align this slot to the head of the bolt on the front cover. Install

the mounting bolt. Tighten bolt to 41 N·m (30 ft. lbs.).

3. Install accessory drive belt (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - INSTALLATION).

4. Check belt indexing marks.

5.7L ENGINE

1. Install tensioner on to the mounting bracket. Tighten bolt to 41 N·m (30 ft. lbs.).

2. Install tensioner and bracket assembly

3. Install accessory drive belt (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - INSTALLATION).

BELTS-DRIVE

DIAGNOSIS AND TESTING

ACCESSORY DRIVE BELT

VISUAL DIAGNOSIS

When diagnosing serpentine accessory drive belts, small cracks that run across the ribbed surface of the belt from
rib to rib , are considered normal. These are not a reason to replace the belt. However, cracks running along a rib
(not across) are not normal. Any belt with cracks running along a rib must be replaced. Also replace the belt if it
has excessive wear, frayed cords or severe glazing.

Refer to ACCESSORY DRIVE BELT DIAGNOSIS CHART for further belt diagnosis.

7 - 20

ACCESSORY DRIVE

NOISE DIAGNOSIS

Noises generated by the accessory drive belt are
most noticeable at idle. Before replacing a belt to
resolve a noise condition, inspect all of the accessory
drive pulleys for alignment, glazing, or excessive end
play.

ACCESSORY DRIVE BELT DIAGNOSIS CHART

CONDITION

POSSIBLE CAUSES

CORRECTION

RIB CHUNKING (One or more ribs
has separated from belt body)

1. Foreign objects imbedded in
pulley grooves.

1. Remove foreign objects from
pulley grooves. Replace belt.

2. Installation damage

2. Replace belt

RIB OR BELT WEAR

1. Pulley misaligned

1. Align pulley(s)

2. Abrasive environment

2. Clean pulley(s). Replace belt if
necessary

3. Rusted pulley(s)

3. Clean rust from pulley(s)

4. Sharp or jagged pulley groove
tips

4. Replace pulley. Inspect belt.

5. Belt rubber deteriorated

5. Replace belt

BELT SLIPS

1. Belt slipping because of
insufficient tension

1. Inspect/Replace tensioner if
necessary

2. Belt or pulley exposed to
substance that has reduced friction
(belt dressing, oil, ethylene glycol)

2. Replace belt and clean pulleys

3. Driven component bearing failure
(seizure)

3. Replace faulty component or
bearing

4. Belt glazed or hardened from
heat and excessive slippage

4. Replace belt.

LONGITUDAL BELT CRACKING

1. Belt has mistracked from pulley
groove

1. Replace belt

2. Pulley groove tip has worn away
rubber to tensile member

2. Replace belt

ACCESSORY DRIVE

7 - 21

CONDITION

POSSIBLE CAUSES

CORRECTION

GROOVE JUMPING

(Belt does not maintain correct
position on pulley)

1. Incorrect belt tension

1. Inspect/Replace tensioner if
necessary

2. Pulley(s) not within design
tolerance

2. Replace pulley(s)

3. Foreign object(s) in grooves

3. Remove foreign objects from
grooves

4. Pulley misalignment

4. Align component

5. Belt cordline is broken

5. Replace belt

BELT BROKEN
(Note: Identify and correct problem
before new belt is installed)

1. Incorrect belt tension

1. Replace Inspect/Replace
tensioner if necessary

2. Tensile member damaged during
belt installation

2. Replace belt

3. Severe misalignment

3. Align pulley(s)

4. Bracket, pulley, or bearing failure

4. Replace defective component
and belt

NOISE
(Objectionable squeal, squeak, or
rumble is heard or felt while drive
belt is in operation)

1. Incorrect belt tension

1. Inspect/Replace tensioner if
necessary

2. Bearing noise

2. Locate and repair

3. Belt misalignment

3. Align belt/pulley(s)

4. Belt to pulley mismatch

4. Install correct belt

5. Driven component induced
vibration

5. Locate defective driven
component and repair

TENSION SHEETING FABRIC
FAILURE
(Woven fabric on outside,
circumference of belt has cracked or
separated from body of belt)

1. Tension sheeting contacting
stationary object

1. Correct rubbing condition

2. Excessive heat causing woven
fabric to age

2. Replace belt

3. Tension sheeting splice has
fractured

3. Replace belt

CORD EDGE FAILURE
(Tensile member exposed at edges
of belt or separated from belt body)

1. Incorrect belt tension

1. Inspect/Replace tensioner if
necessary

2. Belt contacting stationary object

2. Replace belt

3. Pulley(s) out of tolerance

3. Replace pulley

4. Insufficient adhesion between
tensile member and rubber matrix

4. Replace belt

7 - 22

ACCESSORY DRIVE

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