OPERATING AND MAINTENANCE—C.5 17. To    prevent    corrosion,    spray    the    engine    with POWERPART Lay-Up 3.    Do  not  spray  inside  the alternator cooling fan area. NOTE: Before  the  engine  is  started  after  a period  in  storage,  operate  the  starter motor with the engine stop control in the   "off"   position   until   oil   pressure shows    on    the    gauge    or    the    oil warning  light  goes  out.    If  a  solenoid stop control is used, this will have to be disconnected for this operation. If  the  engine  protection  is  done  correctly  according  to the  above  recommendations,  no  corrosion  damage  will normally     occur.          Perkins     Engines     Ltd.,     are     not responsible  for  any  damage  that  occurs  in  relation  to  a service storage period. ENGINE COOLANT The quality of the coolant used can have a large effect on  the  efficiency  and  life  of  the  cooling  system.    The recommendations  given  below  can  be  of  assistance  in the  maintenance  of  a  good  cooling    system      with    frost and/or  corrosion protection. 1. Where possible, use clean soft water. 2. If   an   antifreeze   mixture   is   used   to   prevent   frost damage, it must have an ethylene glycol (ethanediol)  base.    An  antifreeze  that  is  to  one  of the  standards  given  below  or  to  an  equal  standard is   acceptable   if   the   pH   value   is   kept   within   the range of 7.0-8.5 when diluted. U.K. BS 3151:1959 ‘Ethanediol Antifreeze Type B with Sodium Benzoate and Sodium Nitrate Inhibitors'. U.S.A. ASTM 03306-74 ‘Ethylene Glycol Base Engine Coolant'. Australia AS 2108-1977 ‘Antifreeze Compounds and Corrosion Inhibitors for Engine Cooling Systems'. When   Perkins   POWERPART   Antifreeze   is   used,   the correct  mixtures  of  antifreeze  and  water  are  as  given below.    Perkins  POWER  PART  Antifreeze  fully  passes the above standards. Lowest Temp. % Volume Mixture-Ratio by of of POWERPART Vol. POWERPART Protection Needed Antifreeze Antifreeze: Water -12C(  10F) 25 1:3 -18C(    0F) 33 1:2 -25C (-13F) 40 1:1.5 -37C (-34F) 50 2:1 -60C (-76F) 66 2:1 The    quality    of    the    antifreeze    coolant    must    be checked  at  least  once  a  year,  for  example,  at  the start of the cold period. 3. When frost protection is not necessary, it is still an advantage  to  use  an  approved  antifreeze  mixture as  this  gives  protection  against  corrosion  and  also raises  the  boiling  point  of  the  coolant.    A  minimum concentration  of  25%    by  volume  of  antifreeze  is necessary, but it is our recommendation that a 33% concentration by volume is used. If an antifreeze is not used, add a correct corrosion inhibitor mixture to the water. Change the  water/corrosion  inhibitor  mixture  every six   months   or   check   according   to   the   inhibitor manufacturer's recommendations. Note: Some    corrosion    inhibitor    mixtures contain soluble oil which can have an adverse    effect    on    some    types    of water hose. If    the    correct    procedures    are    not    used,    Perkins Engines Ltd.  can riot be held responsible for any frost or corrosion damage. To Drain the Cooling System 1. Remove filler cap from header-tank. 2. Drain  water  from    header  tank  and  engine  cylinder block  by  opening  all  drain  cocks  and  plugs.    The cylinder   block   may   be   flushed   back   through   the drain  points  with  the  thermostat  removed.    If  it  is decided    to    refill    the    fresh    water    system    with antifreeze or corrosion inhibitor, see this page. 3. If the engine is to be layed up for the winter season, the   raw   water   system   should   also   be   drained. Before  commencing  draining,  the  sea  cock  should be  turned  off  and  then  all  drain  cocks  opened  and plugs removed.  The removal of the sea water hose at   the   lowest   point   of   the   engine   will   assist   in complete drainage of the raw water. 4. If  the  engine  is  to  be  left  drained  during  freezing conditions,  1/2  pint  (250  ml)  of  undiluted  antifreeze should   be   added   to   the   oil   coolers   to   prevent freezing  should  any  water  drain  into  the  coolers  if the boat is moved.