Engine: Service and Repair

Engine Replacement

Tools Required

J 36857 Engine Lift Brackets

Removal Procedure




1. Remove the hood. Refer to Hood Replacement Service and Repair in Body Front End.
2. Place fender covers over both fenders.
3. Disconnect the negative battery cable (1). Refer to Battery Negative Cable Disconnection and Connection (C 6/7/8) Battery Negative Cable Disconnection and Connection (C 6/7/8) in Engine Electrical.
4. Disconnect the positive battery cable (2).
5. Remove the air cleaner assembly. Refer to Air Cleaner Assembly Replacement Service and Repair in Engine Controls - 8.1 L.
6. Remove the air conditioning (A/C) compressor. Refer to Compressor Replacement (LG5) Compressor Replacement (LG5)Compressor Replacement (L18) Compressor Replacement (L18) in Heating, Ventilation, and Air Conditioning.
7. Remove the radiator. Refer to Radiator Replacement Radiator Replacement in Engine Cooling.
8. Remove the ignition coils. Refer to Ignition Coil Replacement Service and Repair in Engine Controls - 8.1 L.




9. Relieve the fuel system pressure. Refer to Fuel Pressure Relief Procedures in Engine Controls - 8.1 L.
10. Disconnect the fuel feed (2) and fuel return (4) pipes. Refer to Plastic Collar Quick Connect Fitting Service Procedures in Engine Controls - 8.1 L.




11. Disconnect the throttle stepper motor electrical connector (1).
12. Disconnect the vacuum lines from the engine, as required.
13. Remove the exhaust gas recirculation (EGR) valve. Refer to Exhaust Gas Recirculation Valve Replacement Exhaust Gas Recirculation Valve Replacement in Engine Controls - 8.1 L.
14. Remove the generator mounting bracket. Refer to Generator Bracket Replacement (LG5 without Belt Tensioner) Generator Bracket Replacement (LG5 without Belt Tensioner)Generator Bracket Replacement (LG5 without A/C) Generator Bracket Replacement (LG5 without A/C)Generator Bracket Replacement (LG5 with A/C) Generator Bracket Replacement (LG5 with A/C)Generator Bracket Replacement (L18) Generator Bracket Replacement (L18) in Engine Electrical.
15. Remove the engine electrical harness and tie out of the way.
16. Raise and suitably support the vehicle with safety stands. Refer to Lifting and Jacking the Vehicle Service and Repair in General Information.
17. Remove the hoses from the power steering pump. Refer to Power Steering Cooler Pipe/Hose Replacement Power Steering Cooler Pipe/Hose Replacement in Power Steering System.




18. Remove the ground wire bolt at the engine block.
19. Remove the starter motor. Refer to Starter Motor Replacement (LG5) Starter Motor Replacement (LG5)Starter Motor Replacement (L18) Starter Motor Replacement (L18) in Engine Electrical.
20. Remove the catalytic converter. Refer to Catalytic Converter Replacement Service and Repair in Engine Exhaust.




21. Remove the bolts from the transmission to the engine.

* For the automatic transmission, refer to Transmission Replacement Transmission Replacement in Automatic Transmission - Allison.
* For the manual transmission, refer to Transmission Replacement Service and Repair in Manual Transmission - Medium Duty.

22. Remove the engine oil cooler lines from the engine block. Refer to Engine Oil Cooler Hose/Pipe Replacement (L18) Service and Repair in Engine Cooling.
23. Lower the vehicle.




24. Attach J 36857 to the rear of the right cylinder head and to the left front cylinder head.
Notice: Refer to Fastener Notice in Cautions and Notices.

25. Install the attaching bolt and washer. Use GM P/N 9428217 with GM P/N 15650963.

Tighten the lift bracket bolts to 40 Nm (30 lb ft).




26. Remove the engine front mount bracket-to-crossmember bolts and nuts.




27. Remove the engine rear mount bolt.
28. Remove the engine with a suitable lifting devise.
29. Remove the lift brackets from the cylinder head.

Installation Procedure




1. Attach J 36857 to the rear of the right cylinder head and to the front of the left cylinder head.
2. Install the attaching bolt and washer. Use GM P/N 9428217 with GM P/N 15650963.

Tighten the lift bracket bolts to 40 Nm (30 lb ft).

3. Install the engine with a suitable lifting devise.




4. Install the engine front mount-to-crossmember bolts and nuts until snug.




5. Install the engine rear mount bolt until snug.
6. Remove the J 36857 from the cylinder heads.

* Tighten the engine front mount-to-crossmember bolts to 135 Nm (100 lb ft).
* Tighten the engine rear mount bolts to 50 Nm (37 lb ft).

7. Raise the vehicle.
8. Install the engine oil cooler lines to the engine block. Refer to Engine Oil Cooler Hose/Pipe Replacement (L18) Service and Repair in Engine Cooling.




9. Install the bolts from the transmission to the engine.

* For the automatic transmission, refer to Transmission Replacement Transmission Replacement in Automatic Transmission - Allison.
* For the manual transmission, refer to Transmission Replacement Service and Repair in Manual Transmission - Medium Duty.

10. Install the catalytic converter. Refer to Catalytic Converter Replacement Service and Repair in Engine Exhaust.
11. Install the starter motor. Refer to Starter Motor Replacement (LG5) Starter Motor Replacement (LG5)Starter Motor Replacement (L18) Starter Motor Replacement (L18) in Engine Electrical.




12. Install the ground wire bolt at the engine block.

Tighten the ground bolt to 50 Nm (37 lb ft).

13. Install the hoses to the power steering pump. Refer to Power Steering Cooler Pipe/Hose Replacement Power Steering Cooler Pipe/Hose Replacement in Power Steering System.
14. Lower the vehicle.
15. Position the engine electrical harness.
16. Install the generator mounting bracket. Refer to Generator Bracket Replacement (LG5 without Belt Tensioner) Generator Bracket Replacement (LG5 without Belt Tensioner)Generator Bracket Replacement (LG5 without A/C) Generator Bracket Replacement (LG5 without A/C)Generator Bracket Replacement (LG5 with A/C) Generator Bracket Replacement (LG5 with A/C)Generator Bracket Replacement (L18) Generator Bracket Replacement (L18) in Engine Electrical.
17. Install the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement Exhaust Gas Recirculation Valve Replacement in Engine Controls - 8.1 L.
18. Connect the vacuum lines to the engine, as required.




19. Connect the throttle stepper motor electrical connector (1).




20. Connect the fuel feed (2) and fuel return (4) pipes.
21. Install the ignition coils. Refer to Ignition Coil Replacement Service and Repair in Engine Controls - 8.1 L.
22. Install the radiator. Refer to Radiator Replacement Radiator Replacement in Engine Cooling.
23. Install the A/C compressor. Refer to Compressor Replacement (LG5) Compressor Replacement (LG5)Compressor Replacement (L18) Compressor Replacement (L18) in Heating, Ventilation, and Air Conditioning.
24. Install the air cleaner assembly. Refer to Air Cleaner Assembly Replacement Service and Repair in Engine Controls - 8.1 L.




25. Connect the positive battery cable (2).
26. Connect the negative battery cable (1).
27. Remove the fender covers.
28. Install the hood. Refer to Hood Replacement Service and Repair in Body Front End.
29. Before starting a new engine or one that has been repaired complete the following procedure.

1. Fill the engine with the proper quantity and grade of oil.
2. Add engine oil supplement GM P/N 12345501, Canada P/N 992704, or equivalent to the engine oil.
3. Remove the fuel pump fuse and disconnect the coil harness connectors, then crank the engine until oil pressure is present.
4. Crank the engine several times. Listen for any unusual noises or evidence that any of the parts are binding.
5. Install the fuel pump fuse and connect the coil harness connectors and 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 oil pressure.
7. Run the engine at about 1000 RPM's until the engine has reached normal operating temperature.
8. Inspect for oil and or coolant leaks while the engine is running.
9. Stop the engine and perform a final inspection for the proper engine oil and coolant levels.
10. The final step is to perform the crankshaft position (CKP) sensor variation learn procedure. Refer to Crankshaft Position System Variation Learn Testing and Inspection in Engine Controls - 8.1 L.