Jeep 200 Cherokee Service Manual page 300

XJ
DIAGNOSIS AND TESTING (Continued)
CONDITION
TEMPERATURE GAUGE
READING IS INCONSISTENT
(FLUCTUATES, CYCLES OR
IS ERRATIC)
PRESSURE CAP IS
BLOWING OFF STEAM
AND/OR COOLANT.
TEMPERATURE GAUGE
READING MAY BE ABOVE
NORMAL BUT NOT HIGH.
COOLANT LEVEL MAY BE
HIGH IN COOLANT TANK.
2000 JEEP CHEROKEE
POSSIBLE CAUSES
1. During cold weather operation, with
the heater blower in the high position,
the gauge reading may drop slightly.
Fluctuation is also influenced by loads,
outside temperature and extended idle
time with diesel engines.
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 restarting a
warmed-up (hot) engine.
5. Coolant level low in coolant tank (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 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 water
pump allows air to build up in cooling
system causing thermostat to open late.
1. Pressure relief valve in pressure/vent
cap is defective.
2. Major head gasket leak or cracked
cylinder head.
COOLING SYSTEM
CORRECTION
1. A normal condition. No correction
is necessary.
2. Check operation of gauge and
repair if necessry. Refer to Group
8E, Instrument Panel And Gauges.
3. A normal condition. No correction
is necessary. Gauge reading 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 Testing Cooling System
For Leaks in this group.
6. (a) Check for cylinder head
gasket leaks with a commercially
available Block Leak Tester. Repair
as necessary.
(b) Check for coolant in the engine
oil. Inspect for white steam emitting
from exhaust system. Repair as
necessary.
7. Check water pump and replace
as necessary. Refer to Water
Pumps in this group.
8. Refer to Engine Accessory Drive
Belts in this group. Check and
correct as necessary.
Locate leak and repair as
necessary.
1. Check condition of pressure/vent
cap and cap seals. Refer to
Pressure/Vent Caps in this group.
Replace cap as necessary.
2. Refer to Engine group and repair
as necessary.
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