OPERATING AND MAINTENANCE—C.3 Preventive Maintenance If   a   Perkins   marine   diesel   engine   is   to   give   long   and trouble free service, it is imperative that it be maintained in accordance with the following Periodical Attentions :— It  is  good  engineering  practice  to  check  for  water,  fuel and    lubricating    oil    leaks    and    the    tightness    of    nuts, setscrews and hose clips at each servicing period. It should be noted that the maintenance periods given are on the assumption that the fuel and lubricating oils used are to the specifications given in this workshop manual. Daily or Every 8 hours (whichever occurs first) Check coolant level. Check sump oil level. Check gearbox oil level. Check oil pressure. Every 125 hours or 2 months (whichever occurs first) Clean air intake gauzes or screens. Grease tachometer angle drive connections (where nipple fitted). Every 250 hours or 4 months (whichever occurs first) Drain and renew engine lubricating oil using an approved oil — see appendix. Renew lubricating oil filter element or canister. Check drive belt tension. Clean water trap. Lubricate dynamo rear bush (where fitted). Every 500 hours or 12 months (whichever occurs first) Renew final fuel filter element. Clean lift pump sediment chamber. Drain and clean fuel tank. Renew gearbox lubricating oil (Borg Warner). Every 2,500 hours Arrange  for  examination  of  proprietary   equipment,   i.e., Starter motor, dynamo, alternator, oil cooler, etc. Service atomisers. Check and adjust valve clearance (see Page E.8). Note:  Whilst  a  lubricating  oil  drain  plug  is  fitted,  it  is  not normally possible to drain the oil in the Marine installation. Instead,  a  sump  draining  connection  is  fitted,  to  which  a hand operated pump (supplied as an optional extra) can be attached, for the purpose of pumping out the lubricating oil when necessary. The    sump    draining    connection    is    situated     on     the starboard side of the engine. With  4.236  low-line  engines,  the  sump  drain  pump  is  a standard fitment. POST-DELIVERY CHECKOVER After a customer has taken delivery of his Perkins Marine Diesel  engine.    it  is  advisable.    in  his  own  interest.    that  a general checkover of the engine be carried out after the first 25/50 hours in service. It  is  also  recommended  that  the  following  procedure  be adopted    where    an    engine    has    been    laid    up    for    a considerable period before it is again put into service. The checkover should comprise the following points :— 1. Drain lubricating oil sump and re-fill up to the full mark on   the   dipstick   with   new   clean   oil   (Do   not   overfill). When  the  sump  is  drained  and  it  is  possible  to  gain access to the sump strainer, it should be removed and cleaned. 2. Renew clement or canister of lubricating oil filter. 3. Check external nuts for tightness. 4. Warm up engine and then shut down :  remove rocker assembly.    Retighten  cylinder  head  nuts  setscrews  in the correct sequence as given in Fig. E.11 and to the correct   torque   as   given   on   Page   B.1.      The   correct procedure  for  retightening  of  the  cylinder  head  nuts, setscrews   is   given   on   Page   E.8.      Replace   rocker assembly. 5. Check  and  adjust  valve  clearances  (0.012  in  or  0,30 mm cold) see Page E.8. 6. Check  fuel  pipes  from  tank  to  fuel  injection  pump  for leaks. 7. Check for lubricating oil leaks, and rectify if necessary. 8. Check cooling system for leaks and tighten