2001 DODGE RAM engine

hoses, gasket edges and heater. Seal small leak holes
with a Sealer Lubricant (or equivalent). Repair leak
holes and inspect system again with pressure
applied.
Drops Quickly:Indicates that serious leakage is
occurring. Examine system for external leakage. If
leaks are not visible, inspect for internal leakage.
Large radiator leak holes should be repaired by a
reputable radiator repair shop.
INTERNAL LEAKAGE INSPECTION
Remove engine oil pan drain plug and drain a
small amount of engine oil. If coolant is present in
the pan, it will drain first because it is heavier than
oil. An alternative method is to operate engine for a
short period to churn the oil. After this is done,
remove engine dipstick and inspect for water glob-
ules. Also inspect transmission dipstick for water
globules and transmission fluid cooler for leakage.
WARNING: WITH RADIATOR PRESSURE TESTER
TOOL INSTALLED ON RADIATOR, DO NOT ALLOW
PRESSURE TO EXCEED 110 KPA (20 PSI). PRES-
SURE WILL BUILD UP QUICKLY IF A COMBUSTION
LEAK IS PRESENT. TO RELEASE PRESSURE,
ROCK TESTER FROM SIDE TO SIDE. WHEN
REMOVING TESTER, DO NOT TURN TESTER MORE
THAN 1/2 TURN IF SYSTEM IS UNDER PRESSURE.
Operate engine without pressure cap on radiator
until thermostat opens. Attach a Pressure Tester to
filler neck. If pressure builds up quickly it indicates a
combustion leak exists. This is usually the result of a
cylinder head gasket leak or crack in engine. Repair
as necessary.
If there is not an immediate pressure increase,
pump the Pressure Tester. Do this until indicated
pressure is within system range of 110 kPa (16 psi).
Fluctuation of gauge pointer indicates compression or
combustion leakage into cooling system.
Because the vehicle is equipped with a catalytic
converter,do notremove spark plug cables or short
out cylinders to isolate compression leak.If the needle on dial of pressure tester does not
fluctuate, race engine a few times to check for an
abnormal amount of coolant or steam. This would be
emitting from exhaust pipe. Coolant or steam from
exhaust pipe may indicate a faulty cylinder head gas-
ket, cracked engine cylinder block or cylinder head.
A convenient check for exhaust gas leakage into
cooling system is provided by a commercially avail-
able Block Leak Check tool. Follow manufacturers
instructions when using this product.COMBUSTION LEAKAGE TESTÐWITHOUT
PRESSURE TESTER
DO NOT WASTE reusable coolant. If solution is
clean, drain coolant into a clean container for reuse.
WARNING: DO NOT REMOVE CYLINDER BLOCK
DRAIN PLUGS OR LOOSEN RADIATOR DRAIN-
COCK WITH SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM COOLANT CAN OCCUR.
Drain sufficient coolant to allow thermostat
removal. (Refer to 7 - COOLING/ENGINE/ENGINE
COOLANT THERMOSTAT - REMOVAL). Remove
accessory drive belt (Refer to 7 - COOLING/ACCES-
SORY DRIVE/DRIVE BELTS - REMOVAL).
Add coolant to radiator to bring level to within 6.3
mm (1/4 in) of top of thermostat housing.
CAUTION: Avoid overheating. Do not operate
engine for an excessive period of time. Open drain-
cock immediately after test to eliminate boil over.
Start engine and accelerate rapidly three times, to
approximately 3000 rpm while observing coolant. If
internal engine combustion gases are leaking into
cooling system, bubbles will appear in coolant. If bub-
bles do not appear, internal combustion gas leakage
is not present.
7 - 6 COOLINGBR/BE
COOLING (Continued)

DIAGNOSIS AND TESTING - COOLING SYSTEM
GAS ENGINE
COOLING SYSTEM DIAGNOSISÐGASOLINE ENGINE
CONDITION POSSIBLE CAUSES CORRECTION
TEMPERATURE
GAUGE READS LOW1. Has a Diagnostic Trouble Code (DTC)
been set indicating a stuck open
thermostat?1. (Refer to 25 - EMISSIONS CONTROL -
DESCRIPTION) for On-Board Diagnostics
and DTC information. Replace thermostat
if necessary.
2. Is the temperature sending unit
connected?2. Check the temperature sensor
connector. (Refer to 8 - ELECTRICAL/
INSTRUMENT CLUSTER - SCHEMATIC -
ELECTRICAL) Repair connector if
necessary.
3. Is the temperature gauge operating
OK?3. Check gauge operation. (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER/
ENGINE TEMPERATURE GAUGE -
DESCRIPTION) . Repair as necessary.
4. Coolant level low in cold ambient
temperatures accompanied with poor
heater performance.4. Check coolant level in the coolant
reserve/overflow tank and the radiator.
Inspect system for leaks. Repair leaks as
necessary. Refer to the Coolant section of
the manual text for WARNINGS and
CAUTIONS associated with removing the
radiator cap.
5. Improper operation of internal heater
doors or heater controls.5. Inspect heater and repair as necessary.
(Refer to 24 - HEATING & AIR
CONDITIONING - DIAGNOSIS AND
TESTING) for procedures.
TEMPERATURE
GAUGE READS HIGH
OR THE COOLANT
WARNING LAMP
ILLUMINATES.
COOLANT MAY OR
MAY NOT BE LOST OR
LEAKING FROM THE
COOLING SYSTEM1. Trailer is being towed, a steep hill is
being climbed, vehicle is operated in slow
moving traffic, or engine is being idled
with very high ambient (outside)
temperatures and the air conditioning is
on. Higher altitudes could aggravate
these conditions.1. This may be a temporary condition and
repair is not necessary. Turn off the air
conditioning and attempt to drive the
vehicle without any of the previous
conditions. Observe the temperature
gauge. The gauge should return to the
normal range. If the gauge does not
return to the normal range, determine the
cause for overheating and repair. Refer to
Possible Causes (2-20).
2. Is the temperature gauge reading
correctly?2. Check gauge. (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER -
SCHEMATIC - ELECTRICAL) . Repair as
necessary.
3. Is the temperature warning illuminating
unnecessarily?3. (Refer to 8 - ELECTRICAL/
INSTRUMENT CLUSTER - SCHEMATIC -
ELECTRICAL).
4. Coolant low in coolant reserve/overflow
tank and radiator?4. Check for coolant leaks and repair as
necessary. (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
BR/BECOOLING 7 - 7
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
5. Pressure cap not installed tightly. If cap
is loose, boiling point of coolant will be
lowered. Also refer to the following Step
6.5. Tighten cap
6. Poor seals at the radiator cap. 6. (a) Check condition of cap and cap
seals. Refer to Radiator Cap. Replace
cap if necessary.
(b) Check condition of radiator filler neck.
If neck is bent or damaged, replace
radiator.
7. Coolant level low in radiator but not in
coolant reserve/overflow tank. This
means the radiator is not drawing coolant
from the coolant reserve/overflow tank as
the engine cools7. (a) Check condition of radiator cap and
cap seals. Refer to Radiator Cap in this
Group. Replace cap if necessary.
(b) Check condition of radiator filler neck.
If neck is bent or damaged, replace
radiator.
(c) Check condition of the hose from the
radiator to the coolant tank. It should fit
tight at both ends without any kinks or
tears. Replace hose if necessary.
(d) Check coolant reserve/overflow tank
and tanks hoses for blockage. Repair as
necessary.
8. Incorrect coolant concentration 8. Check coolant. (Refer to
LUBRICATION & MAINTENANCE/FLUID
TYPES - DESCRIPTION).
9. Coolant not flowing through system 9. Check for coolant flow at radiator filler
neck with some coolant removed, engine
warm and thermostat open. Coolant
should be observed flowing through
radiator. If flow is not observed, determine
area of obstruction and repair as
necessary.
10. Radiator or A/C condenser fins are
dirty or clogged.10. Remove insects and debris. (Refer to
7 - COOLING - STANDARD
PROCEDURE).
11. Radiator core is corroded or plugged. 11. Have radiator re-cored or replaced.
12. Aftermarket A/C installed without
proper radiator.12. Install proper radiator.
13. Fuel or ignition system problems. 13. Refer to 14 - Fuel System or 8 -
Electrical for diagnosis and testing
procedures.
14. Dragging brakes. 14. Check and correct as necessary.
(Refer to 5 - BRAKES - DIAGNOSIS AND
TESTING) for correct procedures.
15. Bug screen or cardboard is being
used, reducing airflow.15. Remove bug screen or cardboard.
7 - 8 COOLINGBR/BE
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
16. Thermostat partially or completely
shut.16. Check thermostat operation and
replace as necessary. (Refer to 7 -
COOLING/ENGINE/ENGINE COOLANT
THERMOSTAT - REMOVAL) .
17. Viscous fan drive not operating
properly.17. Check fan drive operation and replace
as necessary. (Refer to 7 - COOLING/
ENGINE/FAN DRIVE VISCOUS CLUTCH
- REMOVAL) .
18. Cylinder head gasket leaking. 18. Check for cylinder head gasket leaks.
(Refer to 7 - COOLING - DIAGNOSIS
AND TESTING).
19. Heater core leaking. 19. Check heater core for leaks. (Refer to
24 - HEATING & AIR CONDITIONING/
PLUMBING - DIAGNOSIS AND
TESTING). Repair as necessary.
TEMPERATURE
GAUGE READING IS
INCONSISTENT
(FLUCTUATES,
CYCLES OR IS
ERRATIC)1. During cold weather operation, with the
heater blower in the high position, the
gauge reading may drop slightly.1. A normal condition. No correction is
necessary.
2. Temperature gauge or engine mounted
gauge sensor defective or shorted. Also,
corroded or loose wiring in this circuit.2. Check operation of gauge and repair if
necessary. (Refer to 8 - ELECTRICAL/
INSTRUMENT CLUSTER - DIAGNOSIS
AND TESTING).
3. Gauge reading rises when vehicle is
brought to a stop after heavy use (engine
still running)3. A normal condition. No correction is
necessary. Gauge should return to normal
range after vehicle is driven.
4. Gauge reading high after re-starting a
warmed up (hot) engine.4. A normal condition. No correction is
necessary. The gauge should return to
normal range after a few minutes of
engine operation.
5. Coolant level low in radiator (air will
build up in the cooling system causing
the thermostat to open late).5. Check and correct coolant leaks. (Refer
to 7 - COOLING - DIAGNOSIS AND
TESTING).
6. Cylinder head gasket leaking allowing
exhaust gas to enter cooling system
causing a thermostat to open late.6. (a) Check for cylinder head gasket
leaks. (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
(b) Check for coolant in the engine oil.
Inspect for white steam emitting from the
exhaust system. Repair as necessary.
7. Water pump impeller loose on shaft. 7. Check water pump and replace as
necessary. (Refer to 7 - COOLING/
ENGINE/WATER PUMP - REMOVAL).
8. Loose accessory drive belt. (water
pump slipping)8. (Refer to 7 - COOLING/ACCESSORY
DRIVE/DRIVE BELTS - DIAGNOSIS AND
TESTING). Check and correct as
necessary.
9. Air leak on the suction side of the
water pump allows air to build up in
cooling system causing thermostat to
open late.9. Locate leak and repair as necessary.
BR/BECOOLING 7 - 9
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
PRESSURE CAP IS
BLOWING OFF STEAM
AND/OR COOLANT TO
COOLANT TANK.
TEMPERATURE
GAUGE READING MAY
BE ABOVE NORMAL
BUT NOT HIGH.
COOLANT LEVEL MAY
BE HIGH IN COOLANT
RESERVE/OVERFLOW
TANK1. Pressure relief valve in radiator cap is
defective.1. Check condition of radiator cap and
cap seals. (Refer to 7 - COOLING/
ENGINE/RADIATOR PRESSURE CAP -
DIAGNOSIS AND TESTING). Replace
cap as necessary.
COOLANT LOSS TO
THE GROUND
WITHOUT PRESSURE
CAP BLOWOFF.
GAUGE READING
HIGH OR HOT1. Coolant leaks in radiator, cooling
system hoses, water pump or engine.1. Pressure test and repair as necessary.
(Refer to 7 - COOLING - DIAGNOSIS
AND TESTING).
DETONATION OR
PRE-IGNITION (NOT
CAUSED BY IGNITION
SYSTEM). GAUGE MAY
OR MAY NOT BE
READING HIGH1. Engine overheating. 1. Check reason for overheating and
repair as necessary.
2. Freeze point of coolant not correct.
Mixture is too rich or too lean.2. Check coolant concentration. (Refer to
LUBRICATION & MAINTENANCE/FLUID
TYPES - DESCRIPTION).
HOSE OR HOSES
COLLAPSE WHILE
ENGINE IS RUNNING1. Vacuum created in cooling system on
engine cool-down is not being relieved
through coolant reserve/overflow system.1. (a) Radiator cap relief valve stuck.
(Refer to 7 - COOLING/ENGINE/
RADIATOR PRESSURE CAP -
DIAGNOSIS AND TESTING). Replace if
necessary
(b) Hose between coolant reserve/
overflow tank and radiator is kinked.
Repair as necessary.
(c) Vent at coolant reserve/overflow tank
is plugged. Clean vent and repair as
necessary.
(d) Reserve/overflow tank is internally
blocked or plugged. Check for blockage
and repair as necessary.
7 - 10 COOLINGBR/BE
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
NOISY VISCOUS
FAN/DRIVE1. Fan blades loose. 1. Replace fan blade assembly. (Refer to
7 - COOLING/ENGINE/RADIATOR FAN -
REMOVAL)
2. Fan blades striking a surrounding
object.2. Locate point of fan blade contact and
repair as necessary.
3. Air obstructions at radiator or air
conditioning condenser.3. Remove obstructions and/or clean
debris or insects from radiator or A/C
condenser.
4. Thermal viscous fan drive has
defective bearing.4. Replace fan drive. Bearing is not
serviceable. (Refer to 7 - COOLING/
ENGINE/FAN DRIVE VISCOUS CLUTCH
- REMOVAL).
5. A certain amount of fan noise may be
evident on models equipped with a
thermal viscous fan drive. Some of this
noise is normal.5. (Refer to 7 - COOLING/ENGINE/FAN
DRIVE VISCOUS CLUTCH -
DESCRIPTION) for an explanation of
normal fan noise.
INADEQUATE HEATER
PERFORMANCE.
THERMOSTAT FAILED
IN OPEN POSITION1. Has a Diagnostic trouble Code (DTC)
been set?1. (Refer to 25 - EMISSIONS CONTROL -
DESCRIPTION) for correct procedures
and replace thermostat if necessary
2. Coolant level low 2. (Refer to 7 - COOLING - DIAGNOSIS
AND TESTING).
3. Obstructions in heater hose/fittings 3. Remove heater hoses at both ends and
check for obstructions
4. Heater hose kinked 4. Locate kinked area and repair as
necessary
5. Water pump is not pumping water
to/through the heater core. When the
engine is fully warmed up, both heater
hoses should be hot to the touch. If only
one of the hoses is hot, the water pump
may not be operating correctly or the
heater core may be plugged. Accessory
drive belt may be slipping causing poor
water pump operation.5. (Refer to 7 - COOLING/ENGINE/
WATER PUMP - REMOVAL). If a slipping
belt is detected, (Refer to 7 - COOLING/
ACCESSORY DRIVE/DRIVE BELTS -
DIAGNOSIS AND TESTING). If heater
core obstruction is detected, (Refer to 24
- HEATING & AIR CONDITIONING/
PLUMBING/HEATER CORE -
REMOVAL).
STEAM IS COMING
FROM THE FRONT OF
VEHICLE NEAR THE
GRILL AREA WHEN
WEATHER IS WET,
ENGINE IS WARMED
UP AND RUNNING,
AND VEHICLE IS
STATIONARY.
TEMPERATURE
GAUGE IS IN NORMAL
RANGE1. During wet weather, moisture (snow,
ice or rain condensation) on the radiator
will evaporate when the thermostat
opens. This opening allows heated water
into the radiator. When the moisture
contacts the hot radiator, steam may be
emitted. This usually occurs in cold
weather with no fan or airflow to blow it
away.1. Occasional steam emitting from this
area is normal. No repair is necessary.
BR/BECOOLING 7 - 11
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
COOLANT COLOR 1. Coolant color is not necessarily an
indication of adequate corrosion or
temperature protection. Do not rely on
coolant color for determining condition of
coolant.1. (Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES -
DESCRIPTION). Adjust coolant mixture
as necessary.
COOLANT LEVEL
CHANGES IN
COOLANT RESERVE/
OVERFLOW TANK.
TEMPERATURE
GAUGE IS IN NORMAL
RANGE1. Level changes are to be expected as
coolant volume fluctuates with engine
temperature. If the level in the tank was
between the FULL and ADD marks at
normal operating temperature, the level
should return to within that range after
operation at elevated temperatures.1. A normal condition. No repair is
necessary.
DIAGNOSIS AND TESTING - COOLING SYSTEM
DIESEL ENGINE
COOLING SYSTEM DIAGNOSISÐDIESEL ENGINE
CONDITION POSSIBLE CAUSES CORRECTION
TEMPERATUREGAUGE READS
LOW1. Vehicle is equipped with a heavy
duty cooling system.1. None. System operating normaly.
2. Temperature gauge not
connected2. Connect gauge.
3. Temperature gauge connected
but not operating.3. Check gauge. Refer (Refer to 8 -
ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND
TESTING)
4. Coolant level low. 4. Fill cooling system. (Refer to 7 -
COOLING - STANDARD
PROCEDURE)
TEMPERATURE GAUGE READS
HIGH. COOLANT MAY OR MAY
NOT BE LEAKING FROM SYSTEM1. Vehicle overloaded, high ambient
(outside) temperatures with A/C
turned on, stop and go driving or
prolonged operation at idle speeds.1. Temporary condition, repair not
required. Notify customer of vehicle
operation instructions located in
Owners Manual.
2. Temperature gauge not
functioning correctly.2. Check gauge. (Refer to 8 -
ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND
TESTING)
3. Air traped in cooling 3. Drain cooling system (Refer to 7 -
COOLING - STANDARD
PROCEDURE) and refill (Refer to 7
- COOLING - STANDARD
PROCEDURE)
4. Radiator cap faulty. 4. Replace radiator cap.
5. Plugged A/C or radiator cooling
fins.5. Clean all debre away from A/C
and radiator cooling fins.
7 - 12 COOLINGBR/BE
COOLING (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
6. Coolant mixture incorrect. 6. Drain cooling system (Refer to 7 -
COOLING - STANDARD
PROCEDURE) refill with correct
mixture (Refer to 7 - COOLING -
STANDARD PROCEDURE).
7. Thermostat stuck shut. 7. Replace thermostat.
8. Bug screen or winter front being
used.8. Remove bug screen or winter
front.
9. Viscous fan drive not operating
properly.9. Check viscous fan (Refer to 7 -
COOLING/ENGINE/FAN DRIVE
VISCOUS CLUTCH - DIAGNOSIS
AND TESTING)
10. Cylinder head gasket leaking. 10. Check for leaking head gaskets
(Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
11. Heater core leaking. 11. Replace heater core.
12. cooling system hoses leaking. 12. Tighten clamps or Replace
hoses.
13. Brakes dragging. 13. Check brakes. (Refer to 5 -
BRAKES/HYDRAULIC/
MECHANICAL - DIAGNOSIS AND
TESTING)
TEMPERATURE GAUGE READING
INCONSISTENT ( ERRATIC,
CYCLES OR FLUCTUATES)1. Heavy duty cooling system,
extream cold ambient (outside)
temperature or heater blower motor
in high position.1. None. System operating normaly.
2. Temperature gauge or gauge
sensor defective.2. Check gauge. (Refer to 8 -
ELECTRICAL/INSTRUMENT
CLUSTER - 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
PROCEDURE).
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
RESERVOIR BOTTLE.
(TEMPERATURE GAUGE MAY
READ HIGH)1. Radiator cap defective. 1. Replace radiator cap.
2. Radiator neck surface damaged. 2. Replace radiator.
BR/BECOOLING 7 - 13
COOLING (Continued)