Chevrolet 2004 Impala Owner's Manual page 300

3. If you have the 3800 V6 engine, remove the
3800 Series II V6 engine cover shield to access the
bleed valve.
3.1. Clean the area around the engine oil fill tube
and cap before removing. Twist the oil fill
tube, with cap attached, counterclockwise
and remove it.
3.2. Lift the engine cover shield at the front, slide
the catch tab out of the engine bracket and
remove the cover shield.
3.3. Put the oil fill tube, with cap attached, in the
valve cover oil fill hole until you're ready to
replace the cover shield.
5-38
4. After the engine cools, open the coolant air bleed
valve or valves.
3400 V6 BLEED
VALVE #1
3400 V6 engine: There are two bleed valves. One
is located on the thermostat housing. The other
is located on the thermostat bypass tube.
3400 V6 BLEED
VALVE #2