Engine Oil Additives; When To Change Engine Oil - GMC 1999 Envoy Owner's Manual

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:
D
Most trips are less than 5 to 10 miles (8 to 16 km).
This is particularly important when outside
temperatures are below freezing.
D
Most trips include extensive idling (such as frequent
- -
driving in stop and go traffic).
D
You operate your vehicle in dusty areas or
-
off road frequently.
D
You frequently tow a trailer or use a carrier on top of
your vehicle.
D
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
occurs first.
If none of them is true, use the long trip/highway
maintenance schedule. Change the oil and filter every
7,500 miles (12 500 km) or 12 months
occurs first. Driving a vehicle with a fully warmed
engine under highway conditions causes engine oil to
break down slower.
Remote Oil Filter
--
whichever
yellowblue
--
whichever
The access door for the
remote oil filter is in the
steering linkage shield
assembly located under the
radiator support. Twist the
screw to unlock or lock the
door. If you open the door,
make sure it is securely
closed when you
are finished.
6-13