GMC 1994 Yukon Owner's Manual page 283

Adding Coolant -Gas Engines
The coolant recovery
tank is located on the
passenger side at the
rear corner of the
engine compartment
To Check Coolant
When your engine is cold, the coolant level should be at COLD, or a little
higher. When your engine is warm, the level should be up to
HOT,
or a little
higher.
To Add Coolant
If you
need more coolant, add the proper mix at the coolant recovery tank.
Add coolant mix at the recovery tank, but be careful not to spill it.
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