TM 5-3805-280-24-2
Engine Tune-Up and Break-In
100
CAUTION: Do not drain coolant until it has
14
cooled below operating temperature. Always
loosen block drain valve slowly to relieve any
excess pressure.
6. Remove and check thermostat(s) (B). (See REMOVE,
TEST, AND INSTALL THERMOSTATS in Group 25.)
7. Drain coolant at drain valve (C) and flush cooling
system. (See FLUSHING AND SERVICING COOLING
SYSTEM in Group 02.)
IMPORTANT: Air must be expelled from cooling
system when system is refilled. Loosen
temperature sending unit fitting at rear
of cylinder head or plug in thermostat
housing (A) to allow air to escape when
filling system. Retighten fitting or plug
when all the air has been expelled.
8. Fill cooling system with recommended concentration of
coolant, clean soft water, and inhibitors. (See ENGINE
COOLANT RECOMMENDATIONS/SPECIFICATIONS
in Group 02.)
9. Run engine until it reaches operating temperature.
Check entire cooling system for leaks.
10. After engine cools, check coolant level.
NOTE: Coolant level should be even with bottom of
radiator filler neck.
11. Check system for holding pressure. (See PRESSURE
TEST COOLING SYSTEM AND RADIATOR CAP in
Group 105.)
A--Thermostat Housing
B--Thermostats
C--Drain Valve
RG,100,JW7635
1921NOV972/2
13-477
