Chevrolet GMC 2002 Owner's Manual Supplement page 22

3500HD Models
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Full Size Van Models
When the engine is cold, the coolant level should be at
or above the COLD mark for 3500HD models, or at or
above the FULL COLD line for Full
If it isn't, you may have a leak at the pressure cap or in
the radiator hoses, heater hoses, radiator, water pump or
somewhere else in the cooling system.
CAUTION:
Heater and radiator hoses, and other engine
parts, can be very hot. Don't touch them.
If you do, you can be burned.
Don't run the engine if there is a leak. If you run
the engine, it could lose all coolant. That could
cause an engine fire, and you could be burned.
Get any leak fixed before you drive the vehicle.
If there seems to be no leak, start the engine again.
See if the engine cooling fan speed increases when
idle speed is doubled by pushing the accelerator
pedal down. If it doesn't, your vehicle needs service.
Turn off the engine.
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Size Van models.
5-5