CAUTION TM 10-3930-643-10 2-23. OPERATION    IN    UNUSUAL    WEATHER.-Continued (4)    Air    cleaner. Check    and    clean    air    precleaner    at    closer    than    normal intervals.     Check     air     cleaner     indicator     frequently.     Notify     organizational maintenance    if    the    red    indicator    fills    the    indicator    viewing    window. (5)    At    halt    or    parking. Park    the    forklift    in    a    shaded    area,    if    possible. c.    Rainy    or    Humid    Conditions. (1)     General. Protect    vehicle    from    moisture.    Keep    operator’s    compartment as    dry    as    possible.    Do    not    operate    an    open    ROPS    forklift    under    these    condi- tions,     unless     necessary. (a)    When    parking    an    open    ROPS    vehicle, the     operator     compartment     should be    protected    or    the    forklift    parked    under    shelter. (b)    Parking    on    a    raised    or    elevated    area    is    recommended. (2)    Fuel    system. Keep     fuel     tank     full     to     cut     down     on     water     collecting     in the    fuel    tank. When    adding    fuel    in    rainy    conditions, the    fuel    tank    filler    opening    should    be protected. (3) Lubrication. Lubricate     according     to     LO     10-3930-643-12. 2-24. OPERATION    IN    DUSTY    OR    SANDY    AREAS. a.     General.     Sand     and     dust     are     abrasive     and     can     cause     wear     on     many     parts     of the    vehicle.    Airborne    sand    and    dust    can    clog    the    radiator    and    air    cleaner. b. Cooling    System.    Be    sure    you    check    the    radiator    frequently    and    keep    air passages    open.    If    coolant    level    is    low,    notify    organizational    maintenance. c.    Air    Cleaner. Inspect    and    clean    precleaner    frequently.    Check    air    cleaner indicator    at    closer    than    normal    intervals.    Notify    organizational    maintenance    if red    indicator    fills    the    indicator    viewing    window. d. Lubrication. Lubricate    according    to    LO    10-3930-643-12.    Lubricate    at more    frequent    intervals.    Take    special    care    cleaning    fittings    and    lubrication openings.    Keep    dust    and    dirt    out    of    lubricants. e.    Tire    Pressure. When    operating    the    forklift    on    soft    sand    at    slow    speeds, the    tire    inflation    pressure    may    be    decreased    to    40    psi    in    the    front    tires    and 25    psi    in    the    rear    tires. Refer to organizational maintenance. After    completing    operation    in    sandy    terrain    the    tire    air pressure    must    be    returned    to    normal    (50    psi)    before resuming    work    on    average    or    hard    surface. Refer    to organizational maintenance. 2-55