GMC 1990 Light Truck Repair Manual page 468

6A3-26 4.3 LITER V-6
installed, add Engine Oil Supplement (GM
part no. 1051396) or equivalent to the engine
oil.
3. Fill the cooling system with the proper coolant.
4. With the ignition " OFF," or disconnected, crank the
engine several times. Listen for any unusual noises
or evidence that any parts are binding.
5. Start the engine and listen for unusual noises.
6
. Run the engine at about 1000 rpm until the engine
is at operating temperature.
7. Listen for improperly adjusted valves or sticking
lifters, and other unusual noises.
8
. Check for oil and coolant leaks while the engine is
running.
9. Using the proper Truck Service Manual or Emission
Control Label for specifications, adjust the ignition
timing, idle rpm and mixture, and governor settings,
if so equipped.