1995 CHEVROLET SUBURBAN engine oil

Turn Signals When Towing a Trailer
When you tow a trailer, your vehicle has to have extra wiring (included in
the optional trailering package). The green arrows
on your instrument panel
will flash whenever
you signal a turn or lane change. Properly hooked up,
the trailer lamps will
also flash, telling other drivers you’re about to turn,
change lanes or stop.
When towing a trailer, the green arrows on your instrument panel will flash
for turns even if the bulbs
on the trailer are burned out. Thus, you may think
drivers behind you are seeing your signal when they are not. It’s important
to check occasionally to be sure the trailer bulbs are still working.
Driving On Grades
Reduce speed and shift to a lower gear before you start down a long or steep
downgrade. If
you don’t shift down, you might have to use your brakes so
much that they would get hot and no longer work well.
On
a long uphill grade, shift down and reduce your speed to around 45 mph
(70 kdh) to reduce the possibility of engine and transmission overheating.
If
you have an automatic transmission you should use DRIVE (3) (or, as
you need to, a lower gear) when towing a trailer. Operating your vehicle in
DRIVE (3) when towing a trailer will minimize heat build-up and extend
the life
of your transmission.
If
you have a manual transmission and you are towing a trailer, it’s better
not to use FIFTH (5) gear. Just drive in FOURTH (4) gear (or, as you need
to,
a lower gear).
When towing at high altitude
on steep uphill grades, consider the following:
Engine coolant will boil at a lower temperature than at normal altitudes. If
you turn your engine off immediately after towing at high altitude on steep
uphill grades, your vehicle may show signs similar
to engine overheating.
To avoid this, let the engine run while parked (preferably on level ground)
with the automatic transmission
in PARK (P) (or the manual transmission
out of gear and the parking brake applied) for a few minutes before turning
the engine off.
If you do get the overheat warning, see “Engine
Overheating” in the Index.
Parking on Hills
You really should not park your vehicle, with a trailer attached, on a hill. If
something goes wrong, your rig could start to move. People can be injured,
and both your vehicle and
the trailer can be damaged.
But
if you ever have to park your rig on a hill, here’s how to do it:
1. Apply your regular brakes, but don’t shift into PARK (P) yet, or in gear
for a manual transmission.
ProCarManuals.com

Maintenance When Trailer Towing
Your vehicle will need service more often when you’re pulling a trailer. See
the Maintenance Schedule for more on this. Things that are especially
important
in trailer operation are automatic transmission fluid (don’t
overfill), engine oil, axle lubricant, belt, cooling system, an\
d brake
adjustment. Each
of these is covered in this manual, and the Index will help
you find them quickly. If you’re trailering, it’s a good idea to review these
sections before you start your trip.
Check periodically to see
that all hitch nuts and bolts are tight.
Trailer Lighting Systems Wiring
See “Trailer Wiring Harness” in the Index.
ProCarManuals.com

If the warning continues, pull over, stop, and park your vehicle right away.
If there’s still no sign of steam, push the accelerator until the engine speed is
about twice as fast as normal idle speed. Bring the engine speed back
to
normal idle speed after two or three minutes. Now see if the warning stops.
But then, if you still have the warning,
turn ofthe engine and get everyone
out
of the vehicle until it cools down.
You may decide not to lift the hood but to get service help right away.
Cooling System - Gasoline Engines
When you decide it’s safe to lift the hood, here’s what you’ll see:
A. Coolant recovery tank
B . Engine fan( s)
C. Radiator pressure cap
If the coolant inside the coolant recovery tank is boiling, don’t do anything
else until
it cools down.
5-1 1
ProCarManuals.com

Cooling System - Diesel Engines
When you decide it’s safe to lift the hood, here’s what you’ll see:
A. Coolant surge tank pressure cap
B. Engine fan(s)
C. Radiator
If the coolant inside the coolant surge tank is boiling, don’t do anything else
until
it cools down.
The coolant level
should be at or above
the
COLD mark. If it
isn’t,
you may have a
leak in the radiator
hoses, heater hoses,
radiator, water pump
1 or somewhere else in
the cooling system.
5-18
ProCarManuals.com

You should ask your service station operators if their gasolines contain
deposit control additives and oxygenates, and
if they have been
reformulated
to reduce vehicle emissions.
Diesel Fuel Requirements and Fuel System
Some states and provinces have restrictions on the purchase of diesel fuel
for light-duty vehicles and require you
to buy permits or pay special taxes.
Some
of these restrictions apply only to residents, and others apply to both
residents and visitors. These restrictions can change.
To learn the current
restrictions
in any state or province, contact your auto club, the police or
other officials.
Fuel Requirements
NOTICE:
Diesel fuel or fuel additives not recommended in this manual
could damage your fuel system and engine. Your warranty
wouldn’t cover this damage. And:
Diesel fuel that has been mixed with engine oil could damage
your engine and emission controls.
Always check with your
service station operator to make sure his diesel fuel has not \
been mixed with engine oil.
If you ever run out of diesel fuel, it can be difficult to restart
your engine. “Running Out
of Fuel,” later in this section, tells
you how to get it started again.
To avoid all this, try never to
let your tank get empty.
What Fuel to Use
For best results, use Number 2-D diesel fuel year-round (above and below
freezing conditions) as
oil companies blend Number 2-D fuel to address
climate differences. Number 1-D diesel fuel may be used
in very cold
temperatures (when it stays below
0°F or -1 8°C); however, it will produce
a power and fuel economy
loss. The use of Number 1-D diesel fuel in warm
or hot climates may result in stalling, poor starting when the engine
is hot
and may damage the fuel injection system.
Diesel fuel may foam when you fill your tank. This can cause the automatic
pump nozzle
to shut off, even though your tank isn’t full. If this happens,
just wait for the foaming
to stop and then continue to fill your tank.
6-4
ProCarManuals.com

Canadian Fuels
Diesel-powered trucks are now equipped with emission control systems that
require the use of diesel fuel with low-sulfur
(.05% by weight) content.
Both low- and higher-sulfur fuels will be available
in Canada. Only
low-sulfur diesel fuels are available
in the United States. It is important that
diesel-powered trucks are refueled with low-sulfur fuel. Use of fuels with
higher-sulfur content will affect the function
of the emission components
and may cause reduced performance, excessive smoke and unpleasant odor.
Cold Weather Operation
Follow the instructions listed previously under the heading “What Fuel to
Use
.”
If you’re driving in very cold temperatures and can’t get a “winterized”
Number
2-D that has been adapted to cold weather or a Number 1-D, you
can use one gallon of kerosene for every two gallons of diesel fuel. Once
you add the kerosene, run your engine for several minutes
so the fuels will
mix. Add kerosene only when
the temperature fills below 0°F (-I 8”C),
because the fuel economy of kerosene isn’t as good as that of diesel fuel.
I NOTICE:
Never use home heating oil or gasoline in your diesel engine.
They can cause engine damage.
In cold weather, your fuel filter may become clogged (waxed). To unclog it,
warm the filter to between 32°F and 50°F (0°C to 10°C). You won’t need
to replace it.
Water in Fuel
Sometimes, water can be pumped into your fuel tank along with your diesel
fuel. This can happen if a service station doesn’t regularly inspect and clean
its fuel tanks, or if it gets contaminated fuel from its suppliers.
ProCarManuals.com

Hesitation or “flat” performance at high speed or during hard acceleration
may be an indication of premature fuel filter plugging due
to dirty or
contaminated fuel. The filter element may need to be changed
if this
happens. See your dealer for assistance.
To drain water:
I. Stop and park the vehicle in a safe place. Turn off the engine and apply
the parking brake.
2. Remove the fuel tank cap.
3. Place a fuel-resistant container under the filter drain hose.
4. With the engine
off? open the
water drain valve
2 to 3 turns.
When standing
in
front of the
vehicle, the valve is located
on the
right side of the
thermostat housing.
5. Start the engine and allow it to idle until clear fuel is observed.
6. Stop the engine and close the water drain valve.
7. Remove the fuel-resistant container and properly dispose of the
contaminated fuel.
To find out how to properly dispose of contaminated
diesel fuel see “What to Do
with Used Oil” in the “Engine Oil (Diesel
Engines)” part, later
in this section.
8. Install the fuel tank cap.
If the WATER IN FUEL light comes on again after driving a short distance
or the engine runs rough or stalls-a large amount of water has probably
been pumped
into the fuel tank. The fuel tank should be purged.
6% CAUTION:
Diesel he1 containing water is still flammable. You could be
burned. If you ever try to drain water from
your fuel, keep
sparks, flames and smoking materials away
from the mixture.
6-7
ProCarManuals.com

Fuels in Foreign Countries (Gasoline
Engines)
If you plan on driving in another country outside the U.S. or Canada,
unleaded
fuel may be hard to find. Do not use leaded gasoline. If you use
even one tankful, your emission controls won’t work well or at all. With
continuous use, spark plugs can get fouled, the exhaust system can corrode,
and your engine oil can deteriorate quickly. Your vehicle’s oxygen sensor
will be damaged. All of that means costly repairs that wouldn’t be covered
by your warranty.
To check on fuel availability, ask an auto club, or contact a major oil
company that does business
in the country where you’ll be driving.
You can
also write us at the following address for advice. Just tell us where
you’re going and give your Vehicle Identification Number
(VIN).
General Motors Overseas Distribution Corporation,
North American Export Sales
(NAES)
1908 Colonel Sam Drive
Oshawa, Ontario
LIH 8P7
Filling Your Tank
The fuel cap is behind
a hinged door on the
left side of your
vehicle.
A CAUTION:
Gasoline vapor is highly flammable. It burns violently, and that
can cause very bad injuries. Don’t smoke if you’re near gasol\
ine
or refueling your vehicle.
Keep sparks, flames, and smoking
materials away from gasoline.
6-1 1
ProCarManuals.com