32 GENERAL INFORMATION AND MAINTENANCE
saw with a fine-toothed blade, cut the fuel
line and make sure to clear the line of metal
particles left from the cutting. Reinstall the
line but do not yet tighten the fittings. Install
the in-line filter (if the filter is marked "in"
and "out," install the "out" side towards the
carburetor), fuel-resistant connecting hoses,
and the clamps. Tighten the hose clamps and
the fuel line fittings at the fuel pump and car-
buretor. Start the engine and check for leaks.
LUBRICATION
Oil and Fuel Recommendations
For 1980 and earlier vehicles, oils having one
of the following service ratings MUST be
used: SE, SE/CC, or SF. For 1981 and later
vehicles, use ONLY SF rated oils; it is O.K.
to use an SF oil with a combination rating,
such as SF/CC. Under the classification sys-
tem developed by the American Petroleum
Institute, the SF rating designates the high-
est quality oil for use in passenger cars. In
view of this, it is recommended that you use
an SF rated oil an ANY Corvette. In addi-
tion, Chevrolet recommends the use of an
SF/Energy Conserving oil. Oils labeled "En-
ergy Conserving (or Saving)," "Fuel (Gas or
Gasoline) Saving," etc. are recommended due
to their superior lubricating qualities (less
friction = easier engine operation) and fuel
saving characteristics. Pick your oil viscosity
with regard to the anticipated temperatures
during the period before your next oil change.
Using the accompanying chart, choose the oil
viscosity for the lowest expected tempera-
ture. You will be assured of easy cold starting
and sufficient engine protection.
NOTE:
Some fuel additives contain chem-
icals that can damage the catalytic con-
verter and/or oxygen sensor on late model
engines. Read all labels carefully before
using any additive in the engine or fuel sys-
tem.
Fuel should be selected for the brand and
octane which performs best with your en-
gine. Judge a gasoline by its ability to pre-
vent "pinging," its engine starting capabili-
ties (cold and hot), and general all-weather
performance. As far as octane rating is con-
cerned, refer to the "General Engine Speci-
fications" chart in Chapter 3 to find your en-
gine and its compression ratio. If the
compression ratio is 9.0:1 or lower, in most
cases a regular grade of gasoline can be used.
Oil Viscosity Selection Chart
Anticipated
Temperature Range
SAE
Viscosity
Above 32°F
10W-40
10W-50
20W-40
20W-50
10W-30
May be used as low
as - 10°F
10W-30
10W-40
Multi-
grade
Consistently below
10°F
5W-20
5W-30
Single-
grade
Above 32°F
30
Temperature between
+32°Fand -10°F
If the compression ratio is 9.0:1-10.0:1, use a
premium grade of fuel. Vehicles with a
compression ratio higher than 10.0:1 (1970
and prior—check the engine chart) should use
a premium leaded fuel, if it is available. Most
oil companies have discontinued leaded pre-
mium gasoline; if you cannot find leaded pre-
mium, it has been recommended by several
enthusiast publications to mix regular leaded
and unleaded premium in a 1:3 proportion (1
part regular leaded to 3 parts unleaded pre-
mium). This mixture will give you the lubri-
cating properties of lead and the added per-
formance of a premium gasoline. Also, mixing
leaded and unleaded fuels will increase the
total octane rating by 1 or more points, de-
pending on the ratings of the gas which is ac-
tually used. DO NOT use straight unleaded
gas in a vehicle designed to use leaded; ex-
cessive valve and valve seat wear will result.
CAUTION:
Unleaded fuel MUST be used
in 1975 and later vehicles equipped with
catalytic converters. Use of leaded fuel in
these vehicles will render the catalytic con-
verter ineffective and damage the oxygen
sensor, if equipped.
Fluid Changes
ENGINE OIL AND FILTER
The mileage figures given in your owner's
manual are the Chevrolet recommended in-
tervals for oil and filter changes assuming av-
erage driving. If your Corvette is being used
under dusty, polluted, or off-road conditions,
change the oil and filter sooner than speci-
fied. The same thing goes for cars driven in
stop-and-go traffic or only for short distances.
Always drain the oil after the engine has
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