Chevrolet 30 Series 1967 Service Manual page 14

LUBRICATION 0-12
ENGINE—GASOLINE
Oil
When the truck is delivered, the engine crankcase is
filled with a high grade oil of the type designated "Serv­
ice MS" (see "Types of Oil" below). It also contains
a special "Anti-Wear" additive to assist in better "mat­
ing" of the moving parts. This oil should be drained
after 6,000 miles or 60 days on 10-30 Series Trucks and
2,000 miles or 60 days on 40-60 Series trucks.
the first miles, check the oil level frequently and
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if it is necessary to add oil, use one of the oils described
under " Oil Viscosity Numbers" in this section.
Oil Viscosity Numbers
SAE Viscosity Numbers indicate only the viscosity or
body of the oil, that is, whether an oil is a light (SAE 5W
or 10W) or a heavy body oil (SAE 20 and higher), and do
not consider or include other properties or quality
factors.
Oils are available which are designed to combine the
easy starting characteristics of the lower SAE Viscosity
Number with the warm weather operating characteristics
of the higher SAE Viscosity Number. These are termed
"multi-viscosity oils"; SAE 5W-20, and SAE 10W-30.
The following chart will serve as a guide for the selec­
tion of the correct SAE Viscosity Number for use under
different atmospheric temperature ranges.
If the lowest The following SAE
anticipated Viscosity oils are
temperature is:
RECOMMENDED:
32°F SAE 20W or SAE 20
0°F SAE 10W
Below 0°F SAE 5W
NOTE: For sustained high speed driving, when
the prevailing daylight temperature is above
90°F. SAE 30 may be used.
Maintaining Crankcase Oil Level
The Oil Gauge Rod is marked "Full" and "Add Oil".
These notations have broad arrows pointing to the level
lines.
The oil level should be maintained between the two
lines; neither going above the "Full" line nor under the
"Add Oil" line.
CAUTION:
Do not overfill, after operating ve­
hicle allow a few minutes for oil to return to
crankcase before checking oil level.
When to Change Crankcase Oil
To insure best performance, low maintenance cost and
long engine life, it is necessary to change the crankcase
oil whenever it becomes contaminated with harmful
foreign materials. Draining the crankcase and replacing
with fresh oil every 60 days or
occurs first is recommended for 10-30 Series models
and every 60 days or 2,000 miles for 40-60 Series models.
Under unfavorable driving conditions such as frequent
long runs at high speeds and high loads, driving under
severe dust conditions, and short runs in cold weather
During
Multi-Viscosity
oils
RECOMMENDED:
SAE 10W-30
SAE 10W-30
SAE 5W-20
miles whichever
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which promote accumulation of moisture condensation in
the crankcase, it becomes necessary to drain the oil
more frequently. For 10-30 Series vehicles in heavy
duty operation involving continuous stop-start or pro­
longed idling, engine oil should be changed after 2,500-
3.000 miles of operation. Always drain oil after it has
reached normal operating temperature. Flushing the
engine with oils or solutions other than a good grade of
SAE 10W engine oil is not recommended.
Crankcase Dilution
A major cause of engine deterioration is crankcase
dilution, which is the thinning of the oil by fuel or fuel
vapors leaking by the piston rings and mixing with the
oil. This condition occurs during engine warm-up, when
the fuel is not thoroughly vaporized and burned. Rapid
warm-up is aided by the thermostatic water control and
the thermostatic heat valve located in the exhaust mani­
fold. Efficient crankcase ventilation drives off fuel va­
pors and aids in the vaporization of raw fuel and water
which may find their way into the crankcase. Sparing use
of the choke, proper engine maintenance and more fre ­
quent oil changes during cold weather short-haul opera­
tions (under miles) will minimize or eliminate the
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danger of crankcase dilution.
Oil Filter
It is recommended that the filter cartridge be changed
after every miles or six months whichever occurs
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first for 10-30 Series models and the first 2,000 miles
and every miles or two months whichever occurs
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first for 40-60 Series models. When 2 qt. filters are in­
stalled, change elements every 8,000 miles. This change
should always be performed when the crankcase oil is
changed.
Heavy sludge deposits found on the oil filter elements
at the time of an oil change must be taken as an indica­
tion that the detergency of the oil has been exhausted.
When this occurs, the oil drain interval should be short­
ened. The removal of abrasive dust, metal particles,
and carbon must be ensured by replacement of the oil
filter elements at the time of an oil change.
DISTRIBUTOR
Cam lubrication - rotate lubricator 1/2 turn every
12.000 miles; replace at 24,000 miles.
Hinged Oiler - fill to top with engine oil every 12,000
miles.
FUEL FILTER
Carburetor Type F ilter - Remove the fuel line and in­
let fitting to replace the filter only if carburetor flooding
occurs.
In-Line Filter - Replace the entire filter every 12,000
miles.
ENGINE—DIESEL
Oil Quality
Satisfactory long-time operation of Heavy-Duty Diesel
Engines requires the use of detergent type "Heavy-Duty
Lubricating Oils". These oils provide better lubrication,
possess more heat resistance, and counteract sludge
formation more effectively than the non-detergent type
CHEVROLET TRUCK SERVICE M ANUAL