Going to torque this manifold back on this afternoon - 2003 5.3L - do I need to put any sort of threadlocker on the bolts first? They all have blue gunk on them from long ago...probably from the factory...is that good enough?

Should I just the bolts back in as is and torque to specs or do I need to put anything on them first?

 

Im ****. I want to do this right the first time.

 

According to this procedure, yes you should...
"Install the intake manifold.
Apply a 5 mm (0.20 in) band of threadlock GM P/N 12345382 (Canadian P/N 10953489), or equivalent to the threads of the intake manifold bolts.
"

2003 Chevrolet Tahoe - 2WD | Avalanche, Escalade, Suburban, Tahoe, Yukon (VIN C/K) Service Manual |
Document ID: 824716
Intake Manifold Replacement
Removal Procedure
Important: The intake manifold, throttle body, fuel rail, and injectors may be removed as a
complete assembly. If not servicing the individual components, remove the manifold as a
complete assembly.
1. Remove the throttle body. Refer to Throttle Body Assembly Replacement in Engine Controls -
4.8L, 5.3L, and 6.0L.
2. Remove the fuel injectors. Refer to Fuel Injector Replacement in Engine Controls - 4.8L, 5.3L,
and 6.0L.
3. Disconnect the following electrical connectors:
4. Remove the knock sensor harness electrical connector from the intake manifold.
5. Set the electrical harness aside.
• The manifold absolute pressure (MAP) sensor (1)
• The knock sensor (2)

Document ID: 824716 Page 1 of 9

6. If equipped with vacuum assisted brakes, remove the vacuum brake booster hose from the
rear of the intake manifold.
7. Remove the positive crankcase ventilation (PCV) hose with valve.
Document ID: 824716 Page 2 of 9

8. Remove the MAP sensor (1) from the intake manifold.
9. Remove the evaporative emission (EVAP) purge solenoid vent tube by performing the
following:
9.1. Remove the EVAP tube end from the solenoid (1).
9.2. Remove the EVAP tube end from the vapor pipe (2).
Document ID: 824716 Page 3 of 9

10. Remove the EVAP purge solenoid bolt (2), solenoid (3), and isolator (1) from the intake
manifold.
11. Loosen the intake manifold bolts.
12. Remove the intake manifold.
Document ID: 824716 Page 4 of 9

13. Remove the intake manifold gaskets (1) from the intake manifold.
14. Discard the old intake manifold gaskets.
15. If required, clean and inspect the intake manifold. Refer to Intake Manifold Cleaning and
Inspection .
Installation Procedure
1. Install NEW intake manifold gaskets (1) to the intake manifold.
Document ID: 824716 Page 5 of 9

2. Install the intake manifold.
3. Apply a 5 mm (0.20 in) band of threadlock GM P/N 12345382 (Canadian P/N 10953489), or
equivalent to the threads of the intake manifold bolts.
Notice: Use the correct fastener in the correct location. Replacement fasteners must be the
correct part number for that application. Fasteners requiring replacement or fasteners
requiring the use of thread locking compound or sealant are identified in the service
procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint
surfaces unless specified. These coatings affect fastener torque and joint clamping force and
may damage the fastener. Use the correct tightening sequence and specifications when
installing fasteners in order to avoid damage to parts and systems.
4. Tighten the intake manifold bolts.
Document ID: 824716 Page 6 of 9

Tighten
1. Tighten the bolts a first pass in sequence to 5 N·m (44 lb in).
2. Tighten the bolts a final pass in sequence to 10 N·m (89 lb in).
5. Install the EVAP purge solenoid (3), isolator (1), and bolt (2) to the intake manifold.
Tighten
Tighten the bolt to 10 N·m (89 lb in).
6. Install the EVAP purge solenoid vent tube to the solenoid (1) and vapor pipe (2).
Document ID: 824716 Page 7 of 9

Important: Lightly coat the MAP sensor seal with clean engine oil before installing.
7. Install the MAP sensor (1) to the intake manifold.
8. Install the PCV hose with valve.
Document ID: 824716 Page 8 of 9

9. If equipped with vacuum assisted brakes, install the vacuum brake booster hose to the rear
of the intake manifold.
10. Route the electrical harness into position over the engine.
11. Connect the knock sensor harness electrical connector to the intake manifold.
12. Connect the following electrical connectors.
13. Install the fuel injectors. Refer to Fuel Injector Replacement in Engine Controls - 4.8L, 5.3L,
and 6.0L.
14. Install the throttle body. Refer to Throttle Body Assembly Replacement in Engine Controls -
4.8L, 5.3L, and 6.0L.
• The MAP sensor (1)
• The knock sensor (2)
Document ID: 824716 Page 9 of 9