Jeep 1987 Wrangler Workshop Manual page 418

IPS ENGINES
COOLING SYSTEMS
Service D i a g n o s i s ( C o n t i n u e d )
Condition
Possible Cause
Correction
HIGH TEMPERATUEE
I N D I C A T I O N -
^ H | M U
O V E R H E A T I N G
JLriLJu
(Continued)
S E E
I S
N
O
T
E
S
LOW TEMPERATURE
I N D I C A T I O N -
UNDERCOOLING
COOLANT L O S S -
B O I L O V E R
(12) Water pump shaft broken or im-
peller loose.
(13) Radiator tubes clogged.
(14) Cooling system clogged.
(15) C a s t i n g flash i n cooling passages.
(16) Brakes dragging.
(17) Excessive engine friction,
(18) Antifreeze concentration over 68%.
(19) Missing air seals.
(20) Faulty gauge or sending unit.
(21) Loss o f coolant flow caused by
leakage or foaming.
(22) Viscous fan drive failed.
(1) Thermostat stuck open.
(2) Faulty gauge or sending unit.
(12) Replace water p u m p .
(13) Flush radiator.
(14) Flush system.
(15) Repair or replace as necessary.
Flash m a y be visible by removing
cooling system components or re-
moving core plugs.
(16) Repair brakes.
(17) Repair engine.
118) Lower antifreeze concentration
percentage.
(19) Replace air seals.
(20) Repair or replace faulty
component.
(21) Repair or replace leaking
component, replace coolant.
(22) Replace unit.
(1)
Replace thermostat.
(2) Repair or replace faulty
component.
Refer to Overheating Causes in addition to the following items
(1) Overfilled cooling system.
(2) Quick shutdown after hard (hot >
run.
(3) Air in system resulting in occasion-
al "burping" of coolant.
(4 ) Insufficient antifreeze allowing cool-
ant boiling point to be too low.
(5> Antifreeze deteriorated because of
age or contamination.
(6) Leaks due to loose hose clamps,
loose nuts, bolts, drain plugs, faulty
hoses, or defective radiator
(1) Reduce coolant level to proper
specification
(2) Allow engine to run at fast idle pri-
or to shutdown.
(3) Purge system.
(4) Add antifreeze to raise boiling
point.
(5) Replace coolant.
(6) Pressure test system to locate
source of leak(s) then repair as
necessary.
N O T E : Immediately after shutdown, the engine enters a condition known as heat soak. This is caused by the cooling systet
being inoperative while engine temperature is still high. If coolant temperature rises above boiling point, expansion an
pressure may push some coolant out of the radiator overflow tube. If this does not occur frequently it is considered normal
81189B
B-184