TM10-3930-660-20 7-3 l RADIATOR   SERVICB/REPLACE/TEST (Cont’d) CHANGING  COOLANT 1. DRAIN ENGINE COOLING SYSTEM. a. Slowly remove radiator cap (4) from radiator (2) and allow pressure to escape. Use suitable containers to catch coolant when draining cooling system in steps lb through le. b. Open drain cock (7) at bottom of radiator  (2). c. Open drain cock (5) at top of engine where heater hose (6) attaches.   Open drain cock (5) only enough to allow air into system. d. Disconnect hose (8) at bottom of overflow tank (1). e. Remove two clamps (9) securing cab heater hoses (6) and (10) to two connectors (11). Tag and remove hoses (6) and (10) from connectors  (11).  Discard  clamps (9). f. Allow all coolant to drain from the  cooling  system. 2. FLUSH  ENGINE  COOLING  SYSTEM. a. b. c. Position cab heater hoses (6) and (10) on two connectors (11) as tagged and secure with two new clamps  (9). Connect hose (8) at bottom of overflow tank (1). Close drain cock (7) at bottom of radiator  (2). 7-4