GMC T-Series 1999, Owner'S Manual, Page: 207 / 344

yellow blue
6-21
Engine Oil
(Caterpillar
R
Diesel Engines)
See your Caterpillar
R
Operation & Maintenance Manual
for information on oil quality and viscosities as well as
the temperature range chart.
Engine Oil (Diesel Engines)
It’s a good idea to check your engine oil level every time
you get fuel. In order to get an accurate reading, the oil
must be warm and the vehicle must be on level ground.
The engine oil dipstick is
located on the driver’s side
at the rear of the cab. You
do not need to tilt the cab to
locate the dipstick.
Turn off the engine and give the oil a few minutes to
drain back into the oil pan. If you don’t, the oil dipstick
might not show the actual level.
Checking Engine Oil
Pull out the dipstick and clean it with a paper towel or a
cloth, then push it back in all the way. Remove it again,
keeping the tip down.
When to Add Engine Oil
If the oil is at or below the ADD line, then you’ll need
to add at least one quart of oil. But you must use the
right kind. This part explains what kind of oil to use. For
crankcase capacity, see “Capacities and Specifications”
in the Index.