Engine Block Heater Installation; Bleeding Air From Cooling System; Engine Flushing; Core Plug Replacement - Jeep 1979 CJ-5 Technical & Service Manual

COOLBNO SYSTEMS
1C-17
Bleeding Air from System
Trapped air will hamper or stop coolant flow or cause
burping of engine coolant out of the radiator.
The coolant control valve must be open to the heater
core, the heater control must be in the HEAT position
and the heater temperature control must be in the full
WARM or HIGH position.
On vehicles without coolant recovery system, bleed air
by operating the engine with a properly filled cooling
system with the radiator cap off until coolant has com-
pletely circulated throughout the engine, or until normal
operating temperature is reached.
Add coolant if necessary, and install radiator cap.
On vehicles with coolant recovery system, fill the sys-
tem with coolant and operate the engine with all coolant
caps in place. After coolant has reached normal oper-
ating temperature, shut engine off and allow system to
cool. Add coolant to recovery bottle as necessary.
N O T E : This procedure may have to be repeated several
cycles to maintain full coolant level at operating
temperatures.
Removing Coolant from Crankcase
If coolant mixes with engine oil, it will clog the oil
lines and cause the pistons to seize. Severe damage to
the engine will result. If coolant has leaked into the
lubricating system, locate the cause for the coolant leak,
such as a faulty head gasket or cracked block, and make
the necessary repairs. After repairing the leak, use Jeep
Crankcase Cleaner, or equivalent, to flush engine.
Engine Flushing
(1) Remove thermostat housing and thermostat. In-
stall thermostat housing.
(2) Attach flushing gun to upper radiator hose at
radiator end.
(3) Attach leadaway hose to water pump inlet.
(4) Connect water supply hose and air supply line to
flushing gun.
(5) Allow engine to fill with water.
(6) When engine is filled, apply air in short blasts,
allowing system to fill between air blasts. Continue until
clean water flows through leadaway hose.
(7) Remove thermostat housing and install thermo-
stat. Install thermostat housing, using replacement gas-
ket. Tighten screws to 13 foot-pounds (18 N®m) torque.
(8) Connect radiator hoses.
(9) Refill cooling system.
Core Plug Replacement
Remove core plugs with hammer, chisel, and prying
tool. Apply a sealer to edges of replacement plug and
position plug with lip to outside of block. Install with
hammer and suitable tool. Refer to Core Plug Sizes
chart.
Core Plug Sizes
Location Diameter
(inches)
Six-Cylinder Head - Left Side (3) 7/8
Eight-Cylinder Heads - Outer Side (2 ea) . . . 1
Eight-Cylinder Cylinder Block (3 ea side) . . . 1 1/2
Eight-Cylinder Heads (1 ea end) 1 1 / 2
Six-Cylinder Block (3 on left side,
1 at rear) 2
Six-Cylinder Head (1 at rear) 2
60248
ENGINE BLOCK HEATER
Installation
(1) Drain coolant from engine.
(2) Remove core plug and install block heater (fig.
1C-18). Tighten six-cylinder T-screw to 20 inch-pounds (2
N®m) torque. Tighten eight-cylinder compression nut to
10 foot-pounds (14 N*m) torque.
ROUTE CORD BETWEEN MOTOR
M O U N T BRACKET A N D BLOCK
TYPICAL 6-CYL. ENGINE
TYPICAL 8-CYL. ENGINE
Fig. 1 C - 1 8 Engine Block Heater installation