Engine Rebuild Guide, Break-In and Tune-Up CAUTION: Do not drain coolant until the coolant temperature is below operating temperature. Always loosen coolant drain valve (A) slowly to relieve any excess pressure. 02 010 6. Remove and check thermostat(s). (See REMOVE AND TEST THERMOSTATS in Group 025.) 20 TS281 –UN–23AUG88 7. Drain and flush cooling system. (See FLUSH AND SERVICE COOLING SYSTEM in Group 002.) IMPORTANT: Air must be expelled from cooling system when system is refilled. Loosen temperature sending unit fitting at rear of cylinder head, bleed plug at top front of cylinder head, or plug in thermostat housing to allow air to escape when filling system.
Retighten fitting or plug when all the air has been expelled. Service Cooling System Safely 8. Fill cooling system with coolant. Follow recommendations in Group 002. (See DIESEL ENGINE COOLANT RECOMMENDATIONS in Group 002.) RG8246 –UN–06DEC97 9. Run engine until it reaches operating temperature. Check entire cooling system for leaks. Coolant Drain Valve 10. After engine cools, check coolant level. A—Coolant Drain Valve 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 Section 04, Group 150.) DPSG,OUO1004,922 –19–01JUL99–2/2 CTM100 (06APR04) 02-010-20 P OWER T ECH 10.5 L & 12.5 L Diesel Engines 040604 PN=68