TM 1-1500-204-23-9 (4) Reciprocating Engines Operable. (a) Cleaning.      Clean   engine   exteriors with PD-680, Type II, dry cleaning solvent in accordance with TM 1-1500-204-23-1.  For cleaning air temperature below 20°F use cleaning compound O-C-1889. (b) Preservation of Liquid Cooling Systems.      Completely   drain   engine   cooling   system including  radiator  and  block.    Refill  cooling  system  in accordance   with   equipment   publications.      Test   anti- freeze  for  desired  protection  after  running  the  engine sufficiently to insure thermostat opening and thoroughly mixing of coolant.  Coat cooling system hoses with O-G- 491 glycerol. (c) Lubrication.        Operate    engine    to warm   oil.      Drain   oil   and   clean   or   replace   filter   as applicable.    Service  engine  with  clean  oil  to  operating level   in   accordance   with   the   appropriate   equipment publications. (d) Intake    System    Gasoline    Engine. Drain fuel tank and add a mixture of 1 1/2 pints of MIL- L21260,  Type  1,  grade  10  oil  to  one  ounce  W-G-800 gum preventative compound to five gallons of gasoline (gasoline/oil  mixture  for  two  cycle  engines).    Start  and operate engine, varying rpm.  After engine has warmed, open  throttle  to  approximately  2/3  operating  rpm  and very slowly pour oil in engine and allow to cool.  Seal all openings  with  MIL-B-131,  class  3,  barrier  material  and PPP-T-60, Type IV, class 1 tape. (5) Reciprocating Engines (Inoperable) (a) Cleaning.  Clean inoperable engines in accordance with paragraph 9-7e (4) (a). (b) Preservation of Liquid Cooling Systems.        Check    anti-freeze    solution    for    adequate protection.    If  protection.    If  protection  is  not  adequate, completely   drain   cooling   system   and   refill   with   the appropriate  anti-freeze  indicated  in  paragraph  9-7e  (4) (b).  The engine thermostat may have to be removed to allow complete draining and insure refilling of the engine block   cooling   jacket.      Coat   all   hoses   with   O-G-491 glycerol. (c) Lubrication.    Drain  oil  and  clean  or replace oil filters as appropriate.  Remove valve covers, oil  pan  and  covers  from  accessory  drives.    Spray  all accessed   areas   with   MIL-L-6529   Type   2.      Corrosion preventative  compound.    Reinstall  all  covers  with  new gaskets  and  tighten  hold  down  nuts  to  specific  torque value.    Remove  all  spark  plugs  and  spray  interior  of each    cylinder    with    MIL-L-6529,    Type    2,    corrosion preventative    compound.        Spray    each    cylinder    with piston at bot- tom   dead   center.      Proceed   in   firing   order   until   all cylinders   have   been   treated.      Without   rotating   crank shaft, provide a final spray of all cylinders.  Clean spark plugs and reinstall.  Seal all intake, exhaust vents, and breather    openings    with    MIL-B-131,    class    3,    barrier material and PPP-T-60, Type 5, class 1, tape. (6) Turbine   Engines.      Clean   and   preserve turbine    engines    in    accordance    with    the    applicable equipment  maintenance  manual.    Clean  inlet  area  of turbine  engines  of  dirt  and  debris.    Install  intake  and exhaust covers and seal with MIL-B-131, class 3, barrier material and PPP-T-60 Type 4, grade 1, tape. (7) Fuel   Systems.      Drain   fuel   tank,   lines, sediment  bowl,  and  fuel  filter.    Clean  or  replace  fuel filter as appropriate.  Remove corrosion from underside of metal fuel caps and apply TT-P-664 primer.  Inspect metal fuel tanks for corrosion.  If excessive corrosion is present, treat in accordance TM 55-1500-344-23.  After inspection   and/or   treatment,   fog   interior   of   tank   with MIL-L6529, Type 2, corrosion preventative compound. (8) Air Cleaners. (a) Oil Bath.  Clean and service oil bath air  cleaners  in  accordance  with  MIL-L-21260,  Type  1, grade 10 lubricating oil and seal the openings with MIL- B-1 31, class 3 barrier material and PPP-T-60, Type 5, class 1 tape. (b) Dry   Type.      Clean   and/or   replace filters as appropriate.  Seal all openings with MIL-B-131, class  3  barrier  material  and  PPP-T-60  Type  4,  class  1 tape. (9) Exhaust Systems.  Coat exposed portions of exhaust system with MIL-C-16173, grade 3, corrosion preventative  compound,  seal  openings  with  MIL-B-131, class 3, barrier material and PPP-T-60, Type 4, class 1 tape. (10) Ignition  Systems.    Lubricate  distributor  or magnets  as  specified  in  equipment  publication.    Coat electrical cables and leads with O-G-491 glycerol. (11) External Drives.  Release tension on drive belts.    Clean  pulleys  and  spray  with  TT-P-664  primer. Coat    exposed    gears    with    MIL-C-16173,    grade    3, corrosion preventative compound. (12)  Gearboxes.          Clean    and    treat    exterior surfaces  of  gearboxes  in  accordance  with paragraph  9-7e  (1).    Service  to  operating level   with   the   lubrication   specified   in   the applicable equipment publications. 9-21