3-104. Heater Coolant Pump (Winterized Models)
a. Removal and Installation.
(1) Drain coolant system below level of
manifold (para 3-20).
(2) Tag and disconnect electrical leads (fig. 3-
(3) Turn coolant pump counter clockwise to
remove from close nipple at manifold.
b. Cleaning and Inspection.
(1) Wipe motor clean with a rag dampened in
an approved cleaning solvent then dry with a clean rag.
(2) Visually inspect electrical leads for
deterioration, motor for external damage, or mounting
hardware for burs, stripped threads, or other damage.
Replace damaged or defective items.
3-105. Thermostat Housing, Thermostat, and
Coolant Lines
a. On Engine Model 687C-18-ES.
(1) Thermostat housing removal and
installation.
(a) Drain coolant system below manifold
level (para 3-20).
(b) Refer to figure 3-81, remove pipe
flange, disconnect bypass line, then remove thermostat
housing and gasket from manifold.
(c) Install in reverse order.
(2) Thermostat housing disassembly and
reassembly. Refer to figure 3-93 and disassemble the
thermostat housing. Reassemble in reverse order.
(3) Cleaning, inspection, and repair.
(a) Clean all parts in an approved
cleaning solvent and dry thoroughly.
(b) Visually inspect all metal parts for
excessive wear, burs, or scoring of surfaces. Inspect
gaskets and seals for tears, deterioration, or other
damage or defect.
(c) Repair by replacing defective or
excessively worn parts. Replace a defective seal or
gasket.
(4) Thermostat removal and installation.
(a) Remove thermostat housing ((1)
above).
(b) Disassemble thermostat housing ((2)
Figure 3-88. Fan guard (engine model DS33TA)
above).
removal and installation.
(c) Remove thermostat for test below.
(d) Install in reverse order.
then remove belts from pulleys. Install in reverse order.
(5) Testing the thermostat.
Note. When twin belts are used, replace belts in
(a) Insert thermostat and a suitable
matched pairs when one is defective.
thermometer in a container of water.
b. Cleaning and Inspection.
(b) Heat water until thermostat is open,
(1) Clean belts with a rag dampened in an
noting temperature when thermostat begins to open, and
approved cleaning solution and dry thoroughly.
when it is fully open. Thermostat should begin to open
(2) Visually inspect belt for fraying, tearing, or
at 165 F, and be fully open at 180 F.
other deterioration. Replace a defective belt(s). See
note in a(2) above.
3-101
