Engine Fan Noise - Hummer 2009 H3 Owner's Manual

5-28 Service and Appearance Care
If No Steam Is Coming From
The Engine Compartment
If an engine overheat warning is
displayed but no steam can be seen
or heard, the problem may not be
too serious. Sometimes the engine
can get a little too hot when the
vehicle:
•
Climbs a long hill on a hot day.
•
Stops after high-speed driving.
•
Idles for long periods in traffic.
•
Tows a trailer. See "Driving
on Grades" under Towing a
Trailer on page 4-42.
If the overheat warning is displayed
with no sign of steam:
1. Turn the air conditioning off.
2. Turn the heater on to the highest
temperature and to the highest
fan speed. Open the windows as
necessary.
3. In heavy traffic, let the engine idle
in N (Neutral) while stopped. If it
is safe to do so, pull off the road,
shift to P (Park) or N (Neutral) and
let the engine idle.
If the temperature overheat gage is
no longer in the overheat zone
or an overheat warning no longer
displays, the vehicle can be driven.
Continue to drive the vehicle
slow for about 10 minutes. Keep a
safe vehicle distance from the
car in front of you. If the warning
does not come back on, continue to
drive normally.
If the warning continues, pull over,
stop, and park the vehicle right away.
If there is no sign of steam, idle the
engine for three minutes while
parked. If the warning is still
displayed, turn off the engine until
it cools down.

Engine Fan Noise

This vehicle has a clutched engine
cooling fan. When the clutch is
engaged, the fan spins faster
to provide more air to cool the
engine. In most everyday driving
conditions, the clutch is not
engaged. This improves fuel
economy and reduces fan noise.
Under heavy vehicle loading,
trailer towing and/or high outside
temperatures, the fan speed
increases when the clutch engages.
So you may hear an increase in
fan noise. This is normal and should
not be mistaken as the transmission
slipping or making extra shifts.
It is merely the cooling system
functioning properly. The fan will
slow down when additional cooling
is not required and the clutch
disengages.
You may also hear this fan noise
when you start the engine. It will go
away as the fan clutch disengages.