TM   9-2350-238-10 OPERATION   IN   UNUSUAL   WEATHER– CONTINUED TOXIC  GAS,  EXTREME  DUST,  OR  DUST  AND SAND   STORMS   –   CONTINUED 3 4 5 6 7 8 When   at   halt,   cover   entire   vehicle   with tarpaulin,   if   possible.   If   entire   vehicle cannot   be   covered,   protect   periscopes against   etching   by   windblown   sand. Also,   protect   engine   compartment against   entry   of   sand   and   dust. Clean   tow   winch   and   boom   winch   wire ropes   more   often   when   operating   in   ex- treme  dust  or  sand.  Wipe  as  much  lubri- cant   from   wire   rope   as   possible. Lubricants   mixed   with   sand   create   an abrasive   paste   that   is   more   damaging   to wire   rope   than   the   lack   of   lubricant. Disassemble  and  clean  machine  gun  at least   once   each   day.   Remove   lubricants on   exposed   and   noncritical   operating   sur- faces   of   machine   gun   and   mount.   This will   prevent   windblown   sand   and   dust from   sticking   to   oil   and   forming   an abrasive,   After   handling,   wipe   machine gun   with   dry   cloths   to   remove   perspira- tion   which   may   cause   rusting.   During sand   or   dust   storms,   keep   machine   gun and   mount   covered,   if   possible.   Clean and   lubricate   machine   gun   and   mount with   lubricating   oil   (PL   special   or   CLP) immediately   upon   leaving   sandy   terrain. Operation   in   sand   or   dust   requires   daily cleaning   of   air   filter   bags.   Extreme   condi- tions   may   require   cleaning   filter   bags more   than   once   a  day.   When   air   filter baskets   are   removed,   inspect   air separators   for   clogging.   If   clogged,   notify unit    maintenance    personnel. Refer   to   page   3-56   for   maintenance   pro- cedures   which   are   required   in   addition   to normal   PMCS   when   vehicle   is   operated in   extreme   dust   or   sand. Check  level  of  battery  acid  in  cells  daily. Electrolyte   level   must   not   drop   below   top of   battery   plates.   If   low,   notify   unit maintenance   personnel.   Batteries   self- discharge   at   a   high   rate   when   not   in   use. If   vehicle   is   parked   for   several   days   in hot   climate,   have   unit   maintenance   per- sonnel   remove   batteries   and   store   in   a cool   place,   if   possible, 9   Extremely   dusty   conditions   may   clog radiators   and   cause   engine   to   overheat. Remove   engine   deck   and   check   condition of   radiators.   If   clogged,   notify   unit maintenance     personnel. EXTREMELY  COLD  WEATHER l l l l l Extreme   cold   will   cause lubricants   to   thicken,   prevent batteries   from   furnishing   suf- ficient   Current   for   cold weather   starting,   and   prevent fuel   from   vaporizing   and   pro- perly   combining   with   air   to form   a   combustible   mixture for   starting. During   extreme   cold   be   very careful   when   moving   vehicle after   a   shutdown.   Thickened lubricants   may   cause   failure of   parts.   Tracks   may   freeze to   the   ground. Cold   weather   practices   and precautions   must   be   follow- ed.   FM   9-207   contains   infor- mation   on   cold   weather   oper- ation   applying   specifically   to this   vehicle.   It   must   be   con- sidered   an   essential   part   of this  manual  and  not  merely  a supplementary   explanation. NOTE For   descriptions   of   operations in   extreme   cold   weather, refer   to   FM   9-207,   FM 31-70,   FM   31-71,   and   FM 90-6. Read   FM   21-306   for   special instructions    on    driving hazards  in  snow,  ice,  and unusual    terrain    encountered under   extreme   cold   conditions. 2 - 1 10