GMC 1996 Sonoma Owner's Manual page 199

When you decide it's safe to lift the hood, here's what
you'll see:
k c :
A
A. Coolant Recovery Tank
B. Radiator Pressure Cap
C. Engine Fan
If your vehicle has air conditioning, the auxiliary
electric fan under the hood can start up even
when the engine is not running and can injure
you. Keep hands, clothing and tools away from
any underhood electric fan.
If the coolant inside the coolant recovery tank is boiling,
don't do anything else until it cools down.
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