TM 9-2320-386-10 2-52 2-13. COLD WEATHER STARTING (BELOW +20°F) (-6.7°C) CAUTION Ensure engine has achieved and maintained an operating temper- ature of 160°F (71°C) or more for at least 15 minutes before shut- down. Failure to do so may result in engine damage. a. Push temperature control knob (2) to CLOSED position. b. Place heater switch (5) in OFF position. c. Start engine (para. 2-12) and raise engine rpm to 1200 for 2 minutes or until engine runs smoothly. NOTE Perform step d. if engine cranks, but fails to start. d. Operating quick-start system. CAUTION • Do not engage starter switch for more than 15 seconds at any time, or with headlights on. If engine does not start in 15 seconds, wait 30 seconds before engaging starter switch. Failure to do this may result in damage to starter. • Do not operate start-aid unless engine is idling rough or being cranked. Doing this may result in damage to engine. (1) Engage starter switch (1). (2) While the engine is cranking, press and hold start-aid button (6) for at least 2 to 3 seconds, then release. (3) Wait 3 to 4 seconds, then repeat steps 1 and 2 if engine does not start. e. Raise engine RPM to 1200 rpm for 2 minutes, or until engine runs smoothly. Repeat quick-start operation if necessary. f. After 2 minutes, or after engine is running smoothly, return engine to normal idle. g. Perform steps j. and k. of para. 2-12. 2-14. RAPID ENGINE WARMUP The following procedures are intended for use only under extreme or unusual conditions, such as heavy windshield frost or when it is difficult to achieve normal operating temperature. .WARNING. Parking brake and service brake must be applied during the engine/transmission cycling. The vehicle must also be blocked and personnel kept clear of vehicle path. Failure to do so may result in injury to personnel or damage to equipment.