Chevrolet 30 Series 1967 Service Manual page 15

oils. These oils are grouped in accordance with their
ability to meet the service requirements common to
Heavy-Duty engine operation.
Oil Changes
It is recommended that new engines be started with
100 hour oil change periods. For highway vehicles this
corresponds to approximately 3,000 miles and for city-
service vehicles approximately 1,000-2,000 miles. The
drain interval may then be gradually increased, or de­
creased following the recommendations of the oil sup­
plier until the most practical oil change period for the
particular service has been established.
At each oil change, besides draining engine crankcase,
drain oil filter and oil cooler. An oil cooler, rear drain-
cock is for oil drain.
Solvents should not be used as flushing oils in running
engines. Dilution of the fresh refill oil supply can occur
which may be detrimental.
TYPE
MIL-L-2104A Generally satisfactory for light general
service with fuels containing less than
(API-DG) 0.5% sulphur.
Supplement 1
All Diesel engines - Normal service
(S-l)
(API-DM)
NOTE: Oils of higher additive levels such as
S-3 (API designation DS) tend to form excessive
ash deposits that could result in engine damage;
such oils are not recommended for use in
Chevrolet Diesel engines.
Multi-Viscosity Lubricating Oils
Multi-Viscosity lubricating oils may be used to facili­
tate starting when prolonged exposure of the engine to
temperature below freezing is unavoidable. Consult your
supplier regarding the performance characteristics of
this type of oil and obtain his assurance of adequate lub­
rication before subjecting the engine to heavy-duty se r­
vice.
Cold Weather Operation
The proper lubricating oil viscosity grade when operat­
ing at temperatures above 30°F. is SAE 30. It is permis­
sible to use a lighter grade of oil in order to facilitate
starting as shown in the following table:
AMBIENT
TEMPERATURE
Above 30 °F
0° to -20°F
OIL FILTER
See "Oil F ilter" under Gasoline Engines.
AIR BOX DRAIN TUBES
With engine running, check for flow of air from air
box drain tubes every
USAGE
VISCOSITY
GRADE
SAE 30
SAE 20-20W
SAE 10W
miles and, if tubes are
6 , 0 0 0
clogged, remove, clean, and reinstall tubes. Air box
drain tubes should be cleaned at tune-up intervals even
though clogged condition is not apparent. If engine is
equipped with air box drain tank, drain sediment periodi­
cally.
FUEL FILTER
Drain daily and replace every 12,000 miles.
FUEL STRAINER
The frame mounted fuel strainer assembly, located
between the fuel pump and fuel tank should be replaced
every miles or oftener if fuel pressure falls below
1 2 , 0 0 0
recommended minimum (35 psi at operating speed).
AIR CLEANER
NOTE: Under prolonged dusty driving condi­
tions, it is recommended that these operations
be performed more often.
Oil Bath Type
- Check every
on Diesel engines). Clean, if necessary, and refill with
engine oil, SAE 50, when temperature is above freezing
and SAE 20 below freezing.
Oil Wetted Paper Element
or test element; if satisfactory, re-use element but re ­
check every 6,000 miles until replaced. Element must
not be washed, oiled, tapped, or cleaned with an air hose.
Oil Wetted Paper Element with
Polyurethane Wrap
Every 12,000 miles inspect air cleaner. Remove poly­
urethane wrap and wash in suitable solvent. Check oil
wetted element and replace if necessary. Check every
miles thereafter until element is replaced.
6 , 0 0 0
GOVERNOR
Replace air filter every 12,000 miles.
BATTERY
Every 6,000 miles clean and oil battery terminals and
oil felt washer. Clean top of battery with diluted am­
monia or soda solution and flush with clean water. Check
state of charge especially in freezing weather.
charged battery may freeze and break.
THROW OUT BEARING
On trucks equipped with a yoke and shaft type release
lever, the release bearing is lubricated by means of a
hose attached to a grease cup. The grease cup is filled
with a graphite type grease and should be rotated one turn
every miles and refilled as required.
6 , 0 0 0
CRANKCASE VENTILATION SYSTEM
Valve Type
Every 12,000 miles or 12 months the valve should be
replaced. Connecting hoses, fittings, flame arrestor and
crankcase breather cap (where used) should be cleaned.
LUBRICATION 0-13
miles ( miles
1 2 , 0 0 0 2 , 0 0 0
- F irst miles inspect
1 2 , 0 0 0
An under­
CHEVROLET TRUCK SERVICE M ANUAL