How tight do I tighten the bolts down on the intake manifold on my 2001 4.3L v6 vortec?

Question edited for clarity and spelling of the model.
Question moved to model category.

For the lower intake:
Step 1 - Tighten down to 62in/lbs (not ft/lbs) Center bolts first then outer bolts - Bring all bolts to finger tight then tighten in 1/4 turn increments till proper torque is achieved.
Step 2 - tighten down to 115in/lbs (not ft/lbs) Center bolts first then outer bolts - Tighten in 1/4 turn increments till proper torque is achieved.

For upper intake
Tighten to 18ft/lbs (not in/lbs) starting from the center and working out in a criss-cross pattern - Bring all bolts to finger tight then tighten in 1/4 turn increments till proper torque is achieved.

https://www.google.com/search?q=buick+lesabre+3.8+intake+manifold+torque+specs

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Lower Intake:

1. Use a skin coat of RTV silicone on both sides of the water passage ports (outer most holes) and put the new lower intake gaskets into place
2. Hand tighten the 13mm head intake bolts and Torque the bolts , starting from the center and working your way out in a circular pattern
3. Torque these bolts in a few small increments until they have reached 250 inch pounds of torque.
4. Upper Intake Plenum:
5. When installing the intake air plenum , be sure to catch the four center bolts and the two side bolts (stiffener brackets) before tightening , The center bolts should be torqued to 250 inch pounds .The fuel rail bolts should be torqued to 100 inch pounds

Remove the manifold and send it out to a machine shop, they can remove repair this broken bolt. Cost about $50.00

Tightening sequence would be to tighten from the center most bolts to the outer most bolts.
Intake Upper Bolts = 18 lb.ft.
Intake Lower Bolts = 10 lb.ft.
Exhaust Manifold Nut = 12 lb.ft
Exhaust Manifold pipe = 22 lb.ft.
Exhaust Manifold Heat Shield = 18 lb.in.
Rocker Arm Torque Nuts = 18 lb.ft.

Hope this helped you ?? if you need more info, get back to me.....

To install:

1. Clean all gasket surfaces completely.
2. Install the intake manifold gaskets with the port blocking plates facing the rear of the engine. Factory gaskets should have the words "This Side Up" visible.
3. Apply gasket sealer to the front and rear sealing surfaces of the engine block.
4. Apply a 0.197 inch (5mm) bead of RTV sealer to the front and rear of the block. Extend the sealer approximately 1 / 2 -inch (13mm) onto the heads.
5. Install the lower intake manifold.
6. Apply sealer to the lower intake manifold bolts prior to installation.
7. Install the bolts and tighten in sequence and in 3 steps as follows:
   1. First step to 26 inch lbs. (3 Nm).
   2. Second step to 106 inch lbs. (12 Nm).
   3. Final step to 11 ft. lbs. (15 Nm).
   
   
8. If removed, install the alternator bracket bolt.
9. Install the coolant by-pass hose.
10. Install the EGR valve.
11. Connect the upper radiator hose to the thermostat housing.
12. Connect the heater hose to the lower intake manifold.
13. Connect the fuel pressure and return lines to the lower intake manifold.
14. Connect the wiring harnesses and brackets to the lower manifold.
15. Install the throttle cable bracket, then attach the throttle cable and the cruise control cable (if equipped).
16. Install the transmission oil level indicator and tube, if equipped.
17. Install the EGR tube, clamp and bolt.
18. Install the PCV valve and hose.
19. Install the A/C compressor and bracket.
20. Install the distributor.
21. Install the upper intake manifold.
22. Fill the cooling system.
23. Connect the negative battery cable.
24. Start the vehicle and check the ignition timing (not adjustable).
25. Verify no oil, coolant, vacuum or fuel leaks.

    

26. Install the intake manifold bolts and tighten them to 35 ft. lbs. (48 Nm) in the sequence shown.
    

on the 2.5 4 cylinder

step 1 18 ft lbs.

step 2 26 ft lbs. except bolt #9 re tighten it to 18 ft. lbs.

step 3 all bolts an additional 90 degrees.

intake manifold bolts 65 ft lbs.

on the 3.3L V6

step 1 35 ft lbs.

step 2 tighten all bolts an additional 130 degrees

step 3 tighten center 4 bolts an additional 30 degrees

intake manifold bolts 88 in. lbs.

Here is the removal procedure, and the procedure is the same for both the V-6 and the V-8 Vortec engines. Also, be certain to put engine oil on the "o"-ring seal for the fuel injector assembly before installing the upper intake. Let me know if you require any further assistance.

REMOVAL:

1. Disconnect the battery negative cable assembly from the battery negative terminal.

2. Remove the air cleaner assembly.

3. Remove the wiring harness connectors and the brackets and move aside.

4. Remove the throttle cable and the bracket from the upper intake manifold.

5. Remove the cruise control cable, (if equipped).

6. Remove the fuel lines from the intake to the rear of the block.

7. Remove the ignition coil and the bracket.

8. Remove the upper intake manifold.

INSTALLATION:

1. Install the upper intake manifold gasket.

2. Install the upper intake manifold. Use care not to pinch the injector lines between the upper and lower intake manifolds.

3. Install the upper intake manifold bolts. Note the marks made at disassembly for proper stud location. Install the two corner studs first in order to help align the two halves. NOTE: Other than the two torque passes listed below, the OE Manufacturer did NOT address or supply a bolt tightening sequence for the upper Intake Manifold for this model year, or other model years where this 2 piece manifold setup is used. A "Play It Safe" final tightening sequence would be to tighten from the center most bolts to the outer most bolts.

4. Tighten the bolts in two steps: a. Tighten the bolts on the first sequence to 5 Nm (44 inch lbs.). b. Tighten the bolts on the final sequence to 10 Nm (88 inch lbs.).

5. Install the purge solenoid and bracket.

6. Install the ignition coil and bracket.

7. Install the PCV hose et the upper intake manifold.

8. Install the fuel lines from the intake at the rear of the block.

9. Install the cruise control cable (if equipped).

10. Install the throttle cable and bracket from the upper intake manifold.

11. Install the wiring harness connectors and brackets.

12. Install the air cleaner assembly.

13. Connect the battery negative cable assembly to the battery negative terminal. - Tighten the bolt to 15 Nm (11 ft. lbs.).

i belive from

Note, removing the upper intake manifold is not necessary when removing lower intake manifold, they are removed as an assembly.
Disconnect negative battery cable. Drain cooling system. Remove air cleaner assembly and inlet duct. Mark and remove distributor. Remove upper radiator hose at thermostat housing. Disconnect accelerator and cruise control cables. Remove heater hoses from intake manifold. Remove EGR pipe.
Disconnect fuel lines at rear of engine. Remove AC compressor and set aside(leave hoses connected). Remove canister purge solenoid. Disconnect theSCPI injector, ignition coil, Ignition Control Module, generator,IAC motor, TP sensor, O2 sensor, Exhaust Gas Recirculation valve and Engine Coolant Temperature sensor wiring harness connectors. Remove PCV valve and hose. Remove lower intake manifold bolts. Remove lower intake manifold.
Installation.
Always use New O-rings when reconnecting fuel lines at rear of engine. Apply a bead of RTV silicone sealer along the front and rear sealing surfaces of the block.See Fig.6. Install new gaskets and intake manifold on block while RTV is still wet to the touch. Use Threadlock 12345382 or equivalent to lower intake manifold bolts. Tighten lower intake manifold bolts in sequence to specification table. See fig. 7. To complete installation, reverse removal procedure.

The Rockerarms--Tighten and then Back off 1/8 of a Turn. Intake Manifold--Tighten Down. Do not Torque them. You could Warp the Intake if too Tight