Dodge 2001 Ram 1500 Owner's Manual page 344

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