Exhaust System - Jeep cherokee 2000 Service Manual

7 - 14 COOLING SYSTEM
DIAGNOSIS AND TESTING (Continued)
CONDITION
TEMPERATURE GAUGE READS
HIGH OR THE COOLANT
WARNING LAMP ILLUMINATES.
COOLANT MAY OR MAY NOT BE
LOST OR LEAKING FROM THE
COOLING SYSTEM (CONTINUED)
TEMPERATURE GAUGE READING
IS INCONSISTENT (FLUCTUATES,
CYCLES OR IS ERRATIC)
POSSIBLE CAUSES
17. Viscous fan drive not operating
properly.
18. Electric cooling fan not
operating properly (vehicles
equipped with 2.5L/4.0L and air
conditioning
19. Cylinder head gasket leaking.
20. Heater core leaking.
1. On vehicles equipped with an
electric fan, the gauge may cycle
up and down. This is due to the
cycling of the electric radiator fan.
2. During cold weather operation,
with the heater blower in the high
position, the gauge reading may
drop slightly.
3. Temperature gauge or engine
mounted gauge sensor defective or
shorted. Also, corroded or loose
wiring in this circuit.
4. Gauge reading rises when
vehicle is brought to a stop after
heavy use (engine still running)
5. Gauge reading high after
re-starting a warmed up (hot)
engine.
6. Coolant level low in radiator (air
will build up in the cooling system
causing the thermostat to open
late).
7. Cylinder head gasket leaking
allowing exhaust gas to enter
cooling system causing a
thermostat to open late.
CORRECTION
17. Check fan drive operation and
replace as necessary. Refer to
Viscous Fan Drive in this Group.
18. Check electric fan operation and
repair as necessary. Refer to
Electric Cooling Fan in this Group.
19. Check for cylinder head gasket
leaks. Refer to Cooling System-
Testing For Leaks in this Group. For
repair, refer to Group 9, Engines.
20. Check heater core for leaks.
Refer to Group 24, Heating and Air
Conditioning. Repair as necessary.
1. This is a normal condition. No
correction is necessary unless the
gauge cycles into the red (overheat)
zone. Refer to Electric Cooling Fan
Diagnosis and Testing in this group.
2. A normal condition. No correction
is necessary.
3. Check operation of gauge and
repair if necessary. Refer to Group
8E, Instrument Panel and Gauges.
4. A normal condition. No correction
is necessary. Gauge should return
to normal range after vehicle is
driven.
5. A normal condition. No correction
is necessary. The gauge should
return to normal range after a few
minutes of engine operation.
6. Check and correct coolant leaks.
Refer to Cooling System-Testing for
leaks in this group.
7. (a) Check for cylinder head
gasket leaks. Refer to Cooling
System-Testing for Leaks in this
group.
(b) Check for coolant in the engine
oil. Inspect for white steam emitting
from the exhaust system. Repair as
necessary.
XJ