1999 CHEVROLET S10 trailer

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As shown in the chart, SAE 5W-30 is best for your
vehicle. However, you can use SAE 10W
-30 if it's going
to be 0F (
-18C) or above. These numbers on an oil
container show its viscosity, or thickness. Do not use
other viscosity oils, such as SAE 20W
-50.
NOTICE:
Use only engine oil with the American Petroleum
Institute Certified For Gasoline Engines
ªStarburstº symbol. Failure to use the
recommended oil can result in engine damage
not covered by your warranty.
GM Goodwrench oil meets all the requirements for
your vehicle.
If you are in an area where the temperature falls below
-20F (-29C), consider using either an SAE 5W-30
synthetic oil or an SAE 0W
-30 oil. Both will provide
easier cold starting and better protection for your engine
at extremely low temperatures.
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
If any one of these is true for you, use the short trip/city
maintenance schedule:

Most trips are less than 5 to 10 miles (8 to 16 km).
This is particularly important when outside
temperatures are below freezing.

Most trips include extensive idling (such as frequent
driving in stop
-and-go traffic).

You operate your vehicle in dusty areas or
off
-road frequently.

You frequently tow a trailer.

The vehicle is used for delivery service, police, taxi
or other commercial application.
Driving under these conditions causes engine oil to
break down sooner. If any one of these is true for your
vehicle, then you need to change your oil and filter
every 3,000 miles (5 000 km) or 3 months
-- whichever
occurs first.

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Refer to the Maintenance Schedule to determine when to
replace the air filter. See ªScheduled Maintenance
Servicesº in the Index.
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.
Automatic Transmission Fluid
When to Check and Change
A good time to check your automatic transmission fluid
level is when the engine oil is changed.
Change both the fluid and filter every 15,000 miles
(25 000 km) if the vehicle is mainly driven under one or
more of these conditions:

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

In hilly or mountainous terrain.

When doing frequent trailer towing.

Uses such as found in taxi, police or delivery service.
If you do not use your vehicle under any of these
conditions, change the fluid and filter every
50,000 miles (83 000 km).
See ªScheduled Maintenance Servicesº in the Index.
How to Check
Because this operation can be a little difficult, you
may choose to have this done at the dealership
service department.

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If you do it yourself, be sure to follow all the
instructions here, or you could get a false reading on
the dipstick.
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 engine
parts or exhaust system parts, starting a fire. Be
sure to get an accurate reading if you check your
transmission fluid.
Wait at least 30 minutes before checking the
transmission fluid level if you have been driving:

When outside temperatures are above 90F (32C).

At high speed for quite a while.

In heavy traffic
-- especially in hot weather.

While pulling a trailer.
To get the right reading, the fluid should be at
normal operating temperature, which is 180F to
200F (82C to 93C).Get the vehicle warmed up by driving about 15 miles
(24 km) when outside temperatures are above
50F (10C). If it's colder than 50F (10C),
drive the vehicle in THIRD (3) until the engine
temperature gage moves and then remains steady for
10 minutes. Then follow the hot check procedures.
Checking Transmission Fluid Cold
A cold check is made after the vehicle has been sitting for
eight hours or more with the engine off and is used only as
a reference. Let the engine run at idle for five minutes if
outside temperatures are 50F (10C) or more. If it's
colder than 50F (10C), you may have to idle the engine
longer. Should the fluid level be low during a cold check,
you must perform a hot check before adding fluid. This
will give you a more accurate reading of the fluid level.
Checking the Fluid Level

Park your vehicle on a level place. Keep the
engine running.

With the parking brake applied, place the shift lever
in PARK (P).

Scheduled Maintenance
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Short Trip/City Definition
Follow the Short Trip/City Scheduled Maintenance if
any one of these conditions is true for your vehicle:

Most trips are less than 5 to 10 miles (8 to 16 km).
This is particularly important when outside
temperatures are below freezing.

Most trips include extensive idling (such as frequent
driving in stop
-and-go traffic).

You operate your vehicle in dusty areas or
off
-road frequently.

You frequently tow a trailer.

If the vehicle is used for delivery service, police, taxi
or other commercial application.
One of the reasons you should follow this schedule if
you operate your vehicle under any of these conditions
is that these conditions cause engine oil to break
down sooner.
Short Trip/City Intervals
Every 3,000 Miles (5 000 km): Engine Oil and Filter
Change (or 3 months, whichever occurs first). Chassis
Lubrication (or 3 months, whichever occurs first). Drive
Axle Service (or 3 months, whichever occurs first).
Every 6,000 Miles (10 000 km): Tire Rotation.
Every 15,000 Miles (25 000 km): Air Cleaner Filter
Inspection, if driving in dusty conditions. Front Wheel
Bearing Repack (2WD only) (or at each brake relining,
whichever occurs first). Automatic Transmission
Service (severe conditions only).
Every 30,000 Miles (50 000 km): Air Cleaner Filter
Replacement. Fuel Filter Replacement.
Every 50,000 Miles (83 000 km): Automatic
Transmission Service (normal conditions).
Every 60,000 Miles (100 000 km): Engine
Accessory Drive Belt Inspection. Fuel Tank, Cap and
Lines Inspection.

Scheduled Maintenance
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Short Trip/City Intervals
Every 100,000 Miles (166 000 km): Spark Plug
Wire Inspection. Spark Plug Replacement. 4.3L V6
Engine Only: Positive Crankcase Ventilation (PCV)
Valve Inspection.
Every 150,000 Miles (240 000 km): Cooling System
Service (or every 60 months, whichever occurs first).
These intervals only summarize maintenance services.
Be sure to follow the complete scheduled maintenance
on the following pages.
Long Trip/Highway Definition
Follow this scheduled maintenance only if none of the
conditions from the Short Trip/City Scheduled
Maintenance is true. Do not use this schedule if the
vehicle is used for trailer towing, driven in a dusty area
or used off paved roads. Use the Short Trip/City
schedule for these conditions.
Driving a vehicle with a fully warmed engine under
highway conditions causes engine oil to break
down slower.

Short Trip/City Scheduled Maintenance
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The services shown in this schedule up to 100,000 miles
(166 000 km) should be performed after 100,000 miles
(166 000 km) at the same intervals. The services shown
at 150,000 miles (240 000 km) should be performed at
the same interval after 150,000 miles (240 000 km).
See ªOwner Checks and Servicesº and ªPeriodic
Maintenance Inspectionsº following.
Footnotes
 The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior to the
completion of the vehicle's useful life. We, however,
urge that all recommended maintenance services be
performed at the indicated intervals and the maintenance
be recorded.
# Lubricate the front suspension, ball joints, steering
linkage, parking brake cable guides, propshaft splines,
universal joints and brake pedal springs.+ A good time to check your brakes is during tire
rotation. See ªBrake System Inspectionº under ªPeriodic
Maintenance Inspectionsº in Part C of this schedule.
** Drive axle service (see ªRecommended Fluids and
Lubricantsº in the Index for proper lubricant to use):

Locking Differential
-- Drain fluid and refill at first
engine oil change. At subsequent oil changes, check
fluid level and add fluid as needed. If driving in
dusty areas or towing a trailer, drain fluid and refill
every 15,000 miles (25 000 km).

Standard Differential
-- Check fluid level and add
fluid as needed at every oil change. If driving in
dusty areas or towing a trailer, drain fluid and refill
every 15,000 miles (25 000 km).

More frequent lubrication may be required for
heavy
-duty or off-road use.

Short Trip/City Scheduled Maintenance
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Inspect air cleaner filter if you are driving in dusty conditions.
Replace filter if necessary.
An Emission Control Service. (See footnote
.)
Check rear/front axle fluid level and add fluid as needed. Check constant
velocity joints and axle seals for leaking. (See footnote **.)
For Two
-Wheel-Drive vehicles only: Clean and repack the front wheel
bearings (or at each brake relining, whichever occurs first).
Change automatic transmission fluid and filter if the vehicle is mainly driven
under one or more of these conditions:
± In heavy city traffic where the outside temperature regularly reaches 90F
(32C) or higher.
± In hilly or mountainous terrain.
± When doing frequent trailer towing.
± Uses such as found in taxi, police or delivery service.
If you do not use your vehicle under any of these conditions, change the fluid
and filter every 50,000 miles (83 000 km).

Short Trip/City Scheduled Maintenance
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30,000 Miles (50 000 km) (Continued)

For Two
-Wheel-Drive vehicles only: Clean and repack the front wheel
bearings (or at each brake relining, whichever occurs first).

Replace fuel filter.
An Emission Control Service. (See footnote
.)
Replace air cleaner filter.
An Emission Control Service.
Change automatic transmission fluid and filter if the vehicle is mainly driven
under one or more of these conditions:
± In heavy city traffic where the outside temperature regularly reaches 90F
(32C) or higher.
± In hilly or mountainous terrain.
± When doing frequent trailer towing.
± Uses such as found in taxi, police or delivery service.
If you do not use your vehicle under any of these conditions, change the fluid
and filter every 50,000 miles (83 000 km).
Rotate tires. See ªTire Inspection and Rotationº in the Index for proper
rotation pattern and additional information. (See footnote +.)