TM 9-2320-361-20 Table 2-2. Mechanical Troubleshooting (Contd). MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION COOLING SYSTEM 18. ENGINE TEMPERATURE GAGE ABOVE 230°F (110°C) Step 1. Step 2. Step 3. Step 4. Step 5. Step 6. Step 7. Step 8. Step 9. WARNING Use caution when removing radiator filler cap. Steam or hot coolant under pressure may cause injury to personnel. Ensure engine fuel supply grade is correct for vehicle use and climatic conditions (TM 9-2320-361-10). If fuel grade is incorrect, completely drain fuel system and replace fuel with correct grade (TM 9-2320-361-10). Check coolant protection level with antifreeze tester. If coolant is not within safe range, service cooling system (para. 3-41). Check engine temperature gage and engine temperature sending unit (table 2-4, malfunction 30). If engine temperature gage is defective, replace (para. 4-12). If engine temperature sending unit is defective, replace (para. 4-24). Inspect drivebelts and pulleys for damage and check belt tension. Replace any damaged parts and adjust drivebelts (para. 4-2). Inspect fan for broken or missing blades. If blades are broken or missing, replace fan (para. 3-40). Inspect radiator for bent fins. Straighten bent fins, or replace radiator (para. 3-42). Start engine. Remove radiator cap and visually check coolant for proper circulation. Stop engine if coolant is not circulating properly, remove thermostat, and test or replace (para. 3-46). Check for clogged or broken radiator (TM 750-254). For cleaning and flushing instructions refer to TB 750-651. Check operation of temperature gage (table 2-4, malfunction 30). END OF TESTING! 19. ENGINE DOES NOT REACH NORMAL OPERATING TEMPERATURE Step 1. Start engine. Remove radiator cap and visually check coolant for proper circulation. Stop engine. If coolant is circulating below 100°F, remove thermostat and test or replace (para. 3-46). Step 2. Test coolant temperature gage, sending unit, and electrical circuits (table 2-4, malfunction 30). END OF TESTING! 20. COOLANT LOSS DURING NORMAL OPERATION Step 1. Pressurize cooling system and check for leaks. a. Tighten loose clamps, fasteners, or fittings. b. Replace leaking hoses and/or water pump (para. 3-43 or 3-47). Step 2. Check radiator cap for proper relief pressure (TM 750-254). Relief pressure should be 15 psi (103 kPa). Replace radiator cap if defective. Step 3. Check for coolant in oil. If coolant is found in oil, notify your supervisor. END OF TESTING! 2-34