GMC 1994 Yukon Owner's Manual page 267

Engine Oil Additives
Don't add anything to your oil. Your GM dealer is ready to advise if you
think something should be added.
When to Change Engine Oil
See if any one of these is true for you:
0
Most trips are less than 4 miles
(6
km).
0
It's below freezing outside and most trips are less than 10 miles (16 km).
0
The engine
is at low speed most of the time (as in door-to-door
delivery, or in stop-and-go traffic).
0
You tow a trailer often.
0
Most trips are through dusty places.
The vehicle is frequently operated off-road.
If any one of these is true for your vehicle, then you need to change your oil
undfilter every 3,000 miles ( 5 000
k m )
or 3 months
-
whichever comes
first.
Light Duty Emissions:
If none of them is true, change the oil every 7,500 miles
( 1
2 500 km) or
12 months
-
whichever comes first. Change the filter at the first oil change
and at every other oil change after that.
Heavy Duty Emissions:
If none of them is true, change the oil every 6,000
miles (1
0
000 km) or
12 months
-
whichever comes first. Change the filter at the first oil change
and at every other oil change after that if mileage determines when you
change your oil. If time determines when you change your oil, change the
filter each time you change your oil.
Engine Coolant Heater (Engine Block Heater)
An engine coolant heater can be a big help if you have to park outside in
very cold weather, 0" F (-1 8°C) or colder. If your vehicle has this option,
see "Engine Coolant Heater
"
in the Index.
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 properly throw away clothing or rags
containing used engine oil. (See the manufacturer's warnings about
the
use
and disposal of oil products.)
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