GMC SIERRA 1994 Manual page 261

A
CAUTION:
Diesel fuel is flammable. It could start a fire if it gets on hot
engine parts. You could be burned. Don't let too much fuel flow
from the air bleed valve, and wipe up any spilled fuel with a
cloth.
3. Close the air bleed valve.
4. Turn the ignition key to "Start" for 10 to 15 seconds at a time until your
engine starts.
Fuel Filter Replacement (Diesel Engines)
If you want to change the fuel filter yourself, here's how to do it:
Before you remove the filter, drain any water that may have collected in the
fuel filter or filter head. See "Water in Fuel" earlier in this section to find
out how to remove water from the fuel system.
Then, drain fuel from the filter by opening the air bleed valve and the water
drain valve. This prevents the fuel from spilling as you replace the filter.
Drain the fuel into a fuel-resistant container and dispose of it properly.
A
CAUTION:
Diesel fuel is flammable. It could start a fire if something ignites
it, and you could be burned. Don't let it get on hot engine parts,
and keep matches or other ignition sources away.
I . Turn off the engine and apply the parking brake.
2. Take off the fuel tank cap. This releases vacuum in the tank.
3. The filter is located at the rear of the intake manifold.
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