Internal Leakage Inspection - Jeep 1987 Wrangler Workshop Manual

ENGINES
COOLING SYSTEMS
D r o p s S l o w l y : Indicates a small leak or
seepage is occurring. Examine all connections
for seepage or slight leakage with a flashlight.
Inspect the radiator, hoses, gasket edges and
heater. Seal small leak holes with AMC Sealer
Lubricant, or equivalent. Repair the leak holes
and reinspect the system with pressure applied.
Drops Quickly: Indicates that a serious leakage
is occurring. Examine the system for serious
external leakage. If no leaks are visible, inspect
for internal leakage.
NOTE: Large radiator leak holes should be
repaired by a reputable radiator repair shop.
Internal Leakage Inspection
Remove the oil pan drain plug and drain a small
amount of engine oil. Coolant, being heavier, will
drain first, or operate the engine to churn the oil,
then examine the dipstick for water globules.
Inspect the transmission dipstick for water
globules.
Inspect the transmission fluid cooler for leakage.
Refer to Transmission Fluid Cooler Leakage
Test.
WARNING: Use extreme caution when the
engine is operating. Do not stand in a direct line
with the fan. Do not put your hands near the
pulleys, belts or fan. Do not wear loose clothing.
Operate the engine without the pressure cap on
the radiator until the thermostat opens.
Attach a pressure tester (J-24460-01) to the filler
neck. If the pressure builds up
quickly, a leak exists as result of a faulty cylinder
head gasket or crack. Repair as necessary.
WARNING: Do not allow pressure to exceed
103.4 kPa (15 psi). Turn the engine Off. To
release the pressure, rock the tester from side to
side. When removing the tester, do not turn the
tester more than 1/2 turn if the system is under
pressure.
J-24460-01
42837
If there is no immediate pressure increase,
pump the pressure tester until the indicated
pressure is within the system range.
Vibration of the gauge pointer indicates
compression or combustion leakage into the
cooling system.
CAUTION: Do not disconnect the spark plug
wires while the engine is operating.
Isolate the compression leak by shorting each
spark plug to the cylinder block. The tester
gauge pointer should stop or decrease vibration
when the spark plug for the leaking cylinder is
shorted because of the absence of combustion
pressure.
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