Chevrolet 70 Series 1970, Service Manual

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53 AND 71 SERIES DIESEL ENGINES 6C-59
NO FUEL OR INSUFFICIENT FUEL
AIR LEAKS
LOW FUEL SUPPLY—Fill fuel tank.
LOOSE CONNECTIONS OR CRACKED FUEL LINES—Tighten connections and replace defec­
tive lines and fittings, then make “Fuel Flow Test.”
DAMAGED FUEL OIL STRAINER GASKET—Replace gasket.
FAULTY INJECTOR TIP ASSEMBLY-Make “Fuel Pressure and Flow Tests” after ascertaining
that all fuel lines and connections are assembled correctly. Replace faulty injectors.
FUEL FLOW
FUEL FILTER OR LINES RESTRICTED—Make “Fuel Pressure and Flow Tests” and clean
primary filter element or replace secondary and injector filter elements, also fuel lines if
necessary.
TEMPERATURE LESS THAN 10°F. ABOVE THE POUR POINT OF FUEL-Refer to
Current Diesel Fuel Oil Service Bulletin.
RESTRICTED FITTING MISSING FROM RETURN MANIFOLD—Install new restricted fitting.
FAULTY FUEL PUMP
RELIEF VALVE NOT SEALING—Make “Fuel Pressure and Flow Tests” and clean and inspect
valve and seat assembly.
WORN GEARS OR PUMP HOUSNG-Replace gear and shaft assembly and fuel pump if housing
is damaged.
FUEL PUMP NOT ROTATING—Check condition of fuel pump drive and blower drive and replace
if necessary.
HIGH LUBRICATING OIL CONSUMPTION
EXTERNAL LEAKS
OIL LINES AND CONNECTIONS LEAKING—Tighten or replace defective parts.
GASKET OR OIL SEAL LEAKS—Replace defective gaskets or oil seals.
HIGH CRANKCASE PRESSURE-Refer to “High Crankcase Pressure”.
EXCESSIVE OIL IN AIR BOX-Refer to “Detonation” in “Abnormal Engine Operation”.
INTERNAL LEAKS
BLOWER OIL SEAL LEAKING—Remove and overhaul blower.
OIL COOLER CORE LEAKING—Replace oil cooler core and use a good cooling system cleaner to
remove oil from water passages.
ENGINE BLOCK END PLATE GASKETS LE AKIN G—Replace block to end plate gaskets.
T-6935
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL