1999 CHEVROLET CORVETTE Owners Manual

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6-15
Your Corvette engine is filled at the factory with a
Mobil 1
synthetic oil, which meets all requirements for
your vehicle.
Substitute Engine Oil: When adding oil to maintain
engine oil level, oil meeting GM Standard GM4718M
may not be available. You can add substitute oil
designated SAE 5W
-30 with the ªStarburstº symbol at
all temperatures. If temperatures are above 0F (
-18C),
you may substitute SAE 10W
-30 with the ªStarburstº
symbol. Substitute oil not meeting GM Standard
GM4718M should not be used for an oil change.
Engine Oil Additives
Don't add anything to your oil. Your dealer is ready to
advise if you think something should be added.
When to Change Engine Oil
Your vehicle has a computer that lets you know when to
change your engine oil. This is not based on mileage,
but on engine revolutions and engine operating
temperature. When the computer has calculated that the
oil needs changing, the Oil Life Monitor will indicate
that a change is necessary. The mileage between oil
changes will vary depending on how you drive your
vehicle
-- usually between 3,000 miles (5 000 km) and
10,000 miles (16 000 km) since your last oil change.Under severe conditions, the indicator may come on
before 3,000 miles (5 000 km). Never drive your vehicle
more than 10,000 miles (16 000 km) or 12 months
(whichever occurs first) without an oil change. Use
engine oil meeting the GM Standard GM4718M.
The system won't detect dust in the oil. So, if you drive
in a dusty area, be sure to change your oil every
3,000 miles (5 000 km) or sooner if the CHANGE OIL
SOON message comes on. Remember to reset the
Engine Oil Life Monitor whenever the oil is changed.
When Changing the Engine Oil
There is a special procedure for changing engine oil,
contact your dealer for additional information or the
procedure can be found in a Corvette Service Manual.
To purchase a service manual, see ªService and Owner
Publicationsº in the Index.
How to Reset the Engine Oil Life Monitor
To reset the monitor after an oil change:
1. With the ignition on, press the TRIP button so the
OIL LIFE percentage is displayed.
2. Press RESET and hold for two seconds. The word
RESET will appear, then OIL LIFE 99%.

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6-16 What to Do with Used Oil
Did you know that used engine oil contains certain
elements that may be unhealthy for your skin and could
even cause cancer? Don't let used oil stay on your skin
for very long. Clean your skin and nails with soap and
water, or a good hand cleaner. Wash or throw away
clothing or rags containing used engine oil. (See the
manufacturer's warnings about the use and disposal of
oil products.)
Used oil can be a real threat to the environment. If you
change your own oil, be sure to drain all free
-flowing oil
from the filter before disposal. Don't ever dispose of oil
by putting it in the trash, pouring it on the ground, into
sewers, or into streams or bodies of water. Instead,
recycle it by taking it to a place that collects used oil. If
you have a problem properly disposing of your used oil,
ask your dealer, a service station or a local recycling
center for help.
Engine Air Cleaner/Filter
Refer to the Maintenance Schedule to determine when to
replace the air filter.
See ªScheduled Maintenance Servicesº in the Index.

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6-17
CAUTION:
Operating the engine with the air cleaner/filter
off can cause you or others to be burned. The air
cleaner not only cleans the air, it stops flame if
the engine backfires. If it isn't there, and the
engine backfires, you could be burned. Don't
drive with it off, and be careful working on the
engine with the air cleaner/filter off.
NOTICE:
If the air cleaner/filter is off, a backfire can cause
a damaging engine fire. And, dirt can easily get
into your engine, which will damage it. Always
have the air cleaner/filter in place when
you're driving.
Air Cleaner/Filter Replacement
To remove the air cleaner/filter:
1. Pull up on the clips on each side to release
the assembly.

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6-18
2. Pull the assembly out.
3. Replace the filter.
4. Push the assembly back into place.
5. Fasten the clips.
Automatic Transmission Fluid
How to Check
Because this operation is difficult, you may choose to
have this done at your dealer service department. It is
not necessary to check the transmission fluid level. A
transmission fluid leak is the only reason for fluid loss.
If a leak occurs, take the vehicle to your dealer service
department and have it repaired as soon as possible.
There is a special procedure for checking and changing
the transmission fluid. Contact your dealer for additional
information or the procedure can be found in a Corvette
Service Manual. To purchase a service manual, see
ªService and Owner Publicationsº in the Index.
NOTICE:
We recommend that only fluid labeled
DEXRON
-III be used, because fluid with
that label is made specially for your automatic
transmission. Damage caused by fluid other than
DEXRON

-III is not covered by your new
vehicle warranty.

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6-19
Change both the fluid and filter every 50,000 miles
(80 000 km) if the vehicle is mainly driven under one of
these conditions:

In heavy city traffic where the outside temperature
regularly reaches 90F (32C) or higher.

In hilly or mountainous terrain.

High performance operation.
If you do not use your vehicle under one of these
conditions, change the fluid and filter every
100,000 miles (166 000 km).
See ªScheduled Maintenance Servicesº in the Index for
the proper service intervals for the transmission fluid
and filter.
Manual Transmission Fluid
When to Check
A good time to have it checked is when the engine oil is
changed. However, the fluid in your manual
transmission doesn't require changing.
How to Check
Because this operation can be difficult, you may choose
to have this done at your Chevrolet dealership
Service Department.
If you do it yourself, be sure to follow all the
instructions here, or you could get a false reading.
NOTICE:
Too much or too little fluid can damage your
transmission. Too much can mean that some
of the fluid could come out and fall on hot
exhaust system parts, starting a fire. Be sure
to get an accurate reading if you check your
transmission fluid.
Check the fluid level only when your engine is off, the
vehicle is parked on a level place and the transmission is
cool enough for you to rest your fingers on the
transmission case.

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Then, follow these steps:
1. Remove the filler plug.
2. Check that the lubricant level is up to the bottom of
the filler plug hole.
3. If the fluid level is good, install the plug and be sure
it is fully seated. If the fluid level is low, add more
fluid as described in the next steps.
How to Add Fluid
Here's how to add fluid. Refer to the Maintenance
Schedule to determine what kind of fluid to use. See
ªRecommended Fluids and Lubricantsº in the Index.
1. Remove the filler plug.
2. Add fluid at the filler plug hole. Add only enough
fluid to bring the fluid level up to the bottom of the
filler plug hole.
3. Install the filler plug. Be sure the plug is fully seated.
4. Tighten the plug to 20 lb
-ft (27 N´m).
Hydraulic Clutch
The clutch linkage in your vehicle is self-adjusting.
The clutch master cylinder reservoir is filled with
hydraulic clutch fluid.
It is not necessary to regularly check clutch fluid unless
you suspect there is a leak in the system. Adding fluid
won't correct a leak.
A fluid loss in this system could indicate a problem.
Have the system inspected and repaired.

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6-21 When to Check and What to Use
Refer to the Maintenance Schedule to determine how
often you should check the fluid level in your clutch
master cylinder reservoir and for the proper fluid. See
ªOwner Checks and Servicesº and ªRecommended
Fluids and Lubricantsº in the Index.
How to Check and Add Fluid
The clutch master cylinder is on the driver's side of the
engine compartment, near the fender.
To check the fluid, remove the cap and rubber seal.
Fluid should be added if the fluid level is below the step
on the inside of the reservoir. There are additional
instructions on the reservoir cap.
Replace the rubber seal and cap.
Rear Axle
When to Check Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant. See ªPeriodic Maintenance
Inspectionsº in the Index.

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6-22 How to Check Lubricant
If the level is below the bottom of the filler plug hole,
you'll need to add some lubricant. Add enough lubricant
to raise the level to the bottom of the filler plug hole.
What to Use
To add lubricant when the level is low, use SAE 75W-90
Synthetic Gear Lubricant (GM Part No. 12378261) or
equivalent meeting GM Specification 9986115. To
completely refill after draining, add 4 ounces (118 ml)
of Limited
-Slip Differential Lubricant Additive
(GM Part No. 1052358) or equivalent. Then fill to
the bottom of the filler plug hole with the Synthetic
Gear Lubricant.
Surge Tank Pressure Cap
NOTICE:
The surge tank pressure cap is a 15 psi (105 kPa)
pressure
-type cap and must be tightly installed to
prevent coolant loss and possible engine damage
from overheating.
When you replace the surge tank pressure cap, a GM cap
is recommended.