After overhaul, the engine must be tested before it is installed in the vehicle. If a suitable test stand is not available, the following procedure can be used after the engine is installed in the vehicle.

1. Fill the crankcase with the proper quantity and grade of oil.
2. Add engine oil supplement GM P/N 1052367 or equivalent to the engine oil.
3. Fill the cooling system with the proper quantity and grade of coolant.

•	Whenever the cooling system is serviced or drained for service procedures, two cooling system sealing pellets GM P/N 3634621 or equivalent, must be added to the cooling system.

•	Cooling system sealing pellets must be crushed prior to installation. The cooling system sealing pellets must be added to the radiator or the pressurized coolant reservoir.

•	Do not place the cooling system sealing pellets into a non-pressurized coolant recovery reservoir. On these systems, the pellets must be added to the radiator.

•	The sealant pellets may leave a film on the sides of the pressurized and non-pressurized coolant recovery reservoirs. This film is normal.

4. With the ignition OFF or disconnected, crank the engine several times. Listen for any unusual noises or evidence that any of the parts are binding.
5. Start the engine and listen for unusual noises.
6. Check the vehicle oil pressure gauge or light and confirm that the engine has acceptable oil pressure.

If necessary, install an oil pressure gauge and measure the engine oil pressure.

7. Run the engine at about 1000 RPM until the engine has reached normal operating temperature.
8. Listen for improperly adjusted or sticking valves, sticking lifters, or other unusual noises.
9. Inspect for oil and/or coolant leaks while the engine is running.
10. Verify that the camshaft position sensor is properly positioned/adjusted (camshaft position sensor procedure).
11. Perform a final inspection for the proper engine oil and coolant levels.