Radiator Reverse Flushing; Transmission Fluid Cooler Repairs; Core Plugs; Cooling System Leakage Tests - Jeep J-10 Series 1982 Technical & Service Manual

Radiator Reverse Flushing
(1) Disconnect radiator hoses from radiator
fittings.
(2) Attach section of radiator hose to radiator bot
tom outlet fitting and insert flushing gun.
(3) Connect water supply hose and air supply hose
to flushing gun. Note excess pressure caution above.
(4) Allow radiator to fill with water.
(5) When radiator is filled, apply air in short blasts,
allowing radiator to refill between blasts.
Continue this reverse flushing until clean water flows
out through radiator upper fitting. If flushing fails to
clear radiator cooling tube passages, have the radiator
cleaned more extensively by a radiator repair shop.
Transmission Fluid Cooler Repairs
Because of the high pressure applied to the fluid
cooler, do not attempt conventional soldering to repair
fractures/holes. All repairs must be silver soldered or
brazed.
Core Plugs
Prior to "hot tanking" for cylinder block cleaning,
remove casting flash causing hot spots or coolant flow
blockage. Remove core plugs with hammer, chisel and
prying tool. Apply a sealer to edges of replacement plugs
and position plugs with lip toward outside of cylinder
block. Install with hammer and suitable tool. Refer to
Core Plug Sizes chart.
Core Plug Sizes
Location
Diameter
inches
m m
Pour-Cylinder Head (rear inside water jacket)
Pour-Cylinder Head (rear)
Four-Cylinder Block (3 on side)
Pour Cylinder Block (1 on rear)
Six-Cylinder Head (3 left side)
Six-Cylinder Head (rear)
Six-Cylinder Block (3 left, 1 rear)
Eight-Cylinder Heads (outer sides, 2 each)
Eight-Cylinder Blocks (3 each side)
Eight-Cylinder Heads (1 each end)
0.637
1.9
1.6
1.9
0.875
2.0
2.0
1.0
1.5
1.5
16
48.5
41.5
48.3
22
51
51
25.4
38.1
38.1
81105
COOLING SYSTEM DIAGNOSIS
If the cooling system requires frequent addition of
coolant to maintain the correct level, inspect all units
and connections in the cooling system for evidence of
leakage. Perform the inspection with the cooling system
cold. Small leaks, which may appear as dampness or
dripping, can easily escape detection if they are rapidly
evaporated by engine heat. Telltale stains of a grayish
white or rusty color, or dye stains from antifreeze, may
appear at connecting joints (e.g., water pump, thermo
stat housing and cylinder head) in the cooling system.
COOLING SYSTEMS 1C-17
These stains are almost always a sure indication of
small leaks, though there may appear to be no defects.
Air may be drawn into the cooling system through
incomplete sealing at the water pump seal or through
incomplete sealing in the coolant recovery system. Com
bustion pressure may be forced into the cooling system
through a fracture in the cylinder head gasket, though
the passage is too small to allow coolant to enter the
combustion chamber. Refer to the applicable diagnosis
chart for specific cooling system faults.
Cooling System Leakage Tests
NOTE: Engine should be warm. Recheck system cold if
cause of coolant loss is not located during warm engine
examination.
WARNING: Hot, pressurized coolant can cause injury
by scalding.
(1) Carefully remove radiator pressure cap from
filler neck and check coolant level.
NOTE: Push down on the cap to disengage from the
stop tabs.
(2) Wipe inside of filler neck and examine lower
inside sealing seat for nicks, cracks, paint, dirt and sol
der residue.
(3) Inspect overflow tube for internal obstructions.
Insert a wire through tube to ensure it is not obstructed.
(4) Inspect cams on outside of filler neck. If cams
are bent, seating of pressure cap valve and tester seal
will be affected. Bent cams can be reformed if done
carefully.
(5) Attach pressure tester to filler neck (fig. 1C-15).
Do not force.
(6) Operate tester pump to apply 15 psi (103.4 kPa)
pressure to system. If hoses swell excessively while test
ing, replace as necessary.
(7) Observe gauge pointer and determine condition
of cooling system according to following criteria.
(a) Holds Steady: if pressure remains constant
for two minutes, there are no serious leaks in the
system.
NOTE: There may be an internal leak that does not
appear with normal system pressure. If it is certain that
coolant is being lost and no leaks can be detected, inspect
for internal leakage or perform Combustion Leakage
Test.
(b) Drops Slowly: indicates small leaks or
seepage is occurring. Examine all connections for seep
age or slight leakage with a flashlight. Inspect radiator,
hose, gasket edges and heater. Seal small holes or frac
tures with AMC Sealer Lubricant, or equivalent. Repair
sources of leaks and recheck system.