GMC 1994 Yukon Owner's Manual page 284

Adding Coolant -Diesel Engines
..
"
.
> C C
-
. .
The coolant surge tank
i '
is located on the
passenger side at the
rear corner of the
engine compartment
To Check Coolani
When your engine is cold, the coolant level should be at the COLD mark,
or a little higher. When your engine is warm, the level should be above the
COLD mark.
If this light comes on,
it
means you're low
on engine coolant.
To Add Coolant
If you need more coolant, add the proper mix ut the surge tank, but only
when the engine is cool.
Open the bleed valve on the thermostat housing
to allow
trapped air out of
the system. Close the bleed valve when coolant begins to flow out.
6-38