Mercedes-Benz Sprinter / Dodge Sprinter. Manual — part 198

CONDITION

POSSIBLE CAUSES

CORRECTION

13. Brakes dragging.

13. Check brakes. (Refer to 5 -
BRAKES/HYDRAULIC/MECHANI-
CAL - DIAGNOSIS AND TESTING)

TEMPERATURE GAUGE READ-
ING INCONSISTENT ( ERRATIC,
CYCLES OR FLUCTUATES)

1. Heavy duty cooling system, ex-
tream cold ambient (outside) tem-
perature or heater blower motor in
high position.

1. None. System operating norma-
ly.

2. Temperature gauge or gauge
sensor defective.

2. Check gauge. (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUS-
TER - DIAGNOSIS AND TESTING)

3. Temporary heavy usage or load.

3. None. Normal condition.

4. Air traped in cooling system.

4. Fill cooling system (Refer to 7 -
COOLING - STANDARD PROCE-
DURE).

5. Water pump

5. Replace water pump.

6. Air leak on suction side of water
pump.

6. Check for leak. (Refer to 7 -
COOLING - DIAGNOSIS AND
TESTING)

RADIATOR CAP LEAKING STEAM
AND /OR COOLANT INTO RES-
ERVOIR BOTTLE. (TEMPERA-
TURE GAUGE MAY READ HIGH)

1. Radiator cap defective.

1. Replace radiator cap.

2. Radiator neck surface damaged.

2. Replace radiator.

HOSE OR HOSES COLLAPSE
WHEN ENGINE IS COOLING.

1. Vacuum created in cooling sys-
tem on engine cool-down is not
being relieved through coolant re-
servior/overflow system.

1. Replace radiator cap, check vent
hose between radiator and reser-
voir bottle for blockage also check
reservoir bottle vent for blockage.

NOISY FAN

1. Fan blade(s) loose, damaged.

1. Replace fan blade assembly.

2. Thermal viscous fan drive.

2. None. Normal condition.

3. Fan blades striking surrounding
objects.

3. Locate contact point and repair
as necessary.

4. Thermal viscous fan drive bear-
ing.

4. Replace viscous fan drive as-
sembly.

5. Obstructed air flow through radi-
ator.

5. Remove obstruction.

INADEQUATE AIR CONDITIONER
PERFORMANCE (COOLING SYS-
TEM SUSPECTED)

1. Radiator and/or A/C condenser
air flow obstructed.

1. Remove obstruction and/or
clean.

2. Thermal viscous fan drive not
working.

2. Check fan drive. (Refer to 7 -
COOLING/ENGINE/FAN DRIVE
VISCOUS CLUTCH - DIAGNOSIS
AND TESTING)

3. Air seals around radiator dam-
aged or missing.

3. Inspect air seals, repair or re-
place as necessary.

VA

COOLING

7 - 3

CONDITION

POSSIBLE CAUSES

CORRECTION

INADEQUATE HEATER PERFOR-
MANCE. GUAGE MAY OR MAY
NOT READ LOW.

1. Heavy duty cooling system, and
cooler ambient temperatures.

1. None. Normal condition.

2. Obstruction in heater hoses.

2. Remove hoses, remove obstruc-
tion.

3. Water pump damaged.

3. Replace water pump.

HEAT ODOR

1. Damaged or missing drive line
heat shields.

1. Repair or replace damaged or
missing heat shields.

2. Thermal viscous fan drive dam-
aged.

2. Check thermal viscous fan drive.
(Refer to 7 - COOLING/ENGINE/
FAN DRIVE VISCOUS CLUTCH -
DIAGNOSIS AND TESTING)

7 - 4

COOLING

VA

ACCESSORY DRIVE

TABLE OF CONTENTS

page

page

BELT TENSIONERS

DESCRIPTION

. . . . . . . . . . . . . . . . . . . . . . . . . . 5

OPERATION

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

DRIVE BELTS

DIAGNOSIS AND TESTING - ACCESSORY

DRIVE BELT

. . . . . . . . . . . . . . . . . . . . . . . . . . 5

REMOVAL

REMOVAL

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

REMOVAL

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

INSTALLATION

INSTALLATION

. . . . . . . . . . . . . . . . . . . . . . . . 8

INSTALLATION

. . . . . . . . . . . . . . . . . . . . . . . . 8

BELT TENSIONERS

DESCRIPTION

CAUTION: Do not attempt to check belt tension with
a belt tension gauge on vehicles equipped with an
automatic belt tensioner.

Drive belts on all engines are equipped with a

spring loaded automatic belt tensioner. This ten-
sioner maintains constant belt tension at all times
and requires no maintenance or adjustment. (Fig. 1)

OPERATION

WARNING: The automatic belt tensioner assembly
is spring loaded. do not attempt to disassemble the
tensioner assembly.

The automatic belt tensioner maintains correct belt

tension using a coiled spring within the tensioner
housing. The spring applies pressure to the tensioner

arm pressing the arm into the belt, tensioning the
belt.

If a new belt is being installed, the arrow must be

within approximately 3 mm (1/8 in.) of indexing
mark. Belt is considered new if it has been used 15
minutes or less. If this specification cannot be met,
check for:

• The wrong belt being installed (incorrect length/

width)

• Worn bearings on an engine accessory (A/C com-

pressor, power steering pump, water pump, idler pul-
ley or generator)

• A pulley on an engine accessory being loose
• Misalignment of an engine accessory
• Belt incorrectly routed.

DRIVE BELTS

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 (Fig. 2), are considered normal.
These are not a reason to replace the belt. However,
cracks running along a rib (not across) are not nor-
mal. Any belt with cracks running along a rib must
be replaced (Fig. 2). 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.

Fig. 1 Accessory Drive Belt

1 - WATER PUMP
2 - ACCESSORY DRIVE BELT
3 - AUTOMATIC BELT TENSIONER
4 - 3/8

9

SQUARE BOLT

5 - MOUNT. BOLT

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ACCESSORY DRIVE

7 - 5

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 contamination, 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 insuffi-
cient tension

1. Inspect/Replace tensioner if nec-
essary

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

2. Replace belt and clean pulleys

3. Driven component bearing fail-
ure (seizure)

3. Replace faulty component or
bearing

4. Belt glazed or hardened from
heat and excessive slippage

4. Replace belt.

Fig. 2 Belt Wear Patterns

1 - NORMAL CRACKS BELT OK
2 - NOT NORMAL CRACKS REPLACE BELT

7 - 6

ACCESSORY DRIVE

VA