ARMY  TM  9-6115-464-12 AIR FORCE TO 35C2-3-445-1 NAVY NAVFAC P-8-624-12 2-13  EXERCISE OF ENGINE ON STANDBY SERVICE. a. General. The diesel engine of a generator set on standby service which is normally operated under opti- mum conditions should be exercised at least every 30 days. However, under any extreme environmental condition, the interval between exercise periods should be shortened appropriately. The exercise period should be long enough to enable the engine to attain normal operating temperature. b.   Exercise   Procedures. (1) Perform the before operation checks and services of Table 2-2. (2)  Refer  to  paragraph  2-6  and  start  the  engine. (3) After allowing sufficient warm up time, run the engine at full speed for the period of time required to obtain two consecutive coolant temperature readings at a 15 minute interval of 160° F (71° C) minimum. (4) Allow the engine to run an additional 30 minutes while performing the during operation checks and services listed in Table 2-2. (5) Refer to paragraph 2-7 and stop the engine. (6) Perform the after operation checks and services listed in Table 2-2. (7) Correct any deficiences noted during or after operation. c. Servicing an Engine on Standby. (1) Change engine oil and oil filter element at a maximum of 6 months. (2) Replace the fuel filter elements at a maximum of 12 months. Table 2-1. Freezing Points, Composition and Specific Gravities of Military Anti-freeze Materials Pints of inhibited Lowest expected Ethylene glycol coolant gylcol per gal. of Compound, antifreeze solution specific ambient  temp.°F coolant ¹ Arctic² gravity at 68 °F³ +20 1 1/2 Issued full strength and ready 1.022 +10 2 mixed for 0- to -65°F 1.036 2 3/4 temperatures  for  both 1.047 -10 3 1/4 initial installation and 1.055 -20 3 1/2 replenishment of losses. 1.062 -30 4 1.067 -40 4 1/4 1.073 -50 Arctic anti-freeze DO NOT DILUTE WITH -60 preferred WATER  OR  ANY  OTHER -75 SUBSTANCE. ¹Maximum protection is obtained at 60 percent by volume (4.8 pints of ethylene glycol per gallon of solution). ²Military Specification MIL-C-11755 Arctic type, nonvolatile anti-freeze compound is intended for use in the cooling system of liquid-cooled internal combustion engines. It is used for protection against freezing primarily in Arctic regions where the ambient temperature remains for extended periods close to -40°F or drops below, to as low as  -90°F. ³Use an accurate hydrometer. To test hydrometer, use 1 part ethylene glycol anti-freeze to 2 parts water. This should produce a hydrometer reading of 0°F. 2-23