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N62 8 Cylinder Intake Manifold Replacement
 
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Pelican Technical Article:

N62 8 Cylinder Intake Manifold Replacement

Nick Czerula

Time:

4 hours4 hrs

Tab:

$350

Talent:

*****

Tools:

Flathead screwdriver, T30, T45 Torx, 11mm socket (socket set), Allen bits

Applicable Models:

BMW E53 X5 Sport Utility (2000-06)
BMW E65 745i Sedan (2002-05)
BMW E65 Alpina B7 Sedan (2007-08)
BMW E66 745Li Sedan (2002-05)
BMW 545i Sedan (2004-05)
BMW 645Ci Coupe/Conv (2004-05)

Parts Required:

Intake manifold gaskets, secondary air pipes and mounts, coolant line

Hot Tip:

Work with a cool engine

Performance Gain:

Seal vacuum leaks, repair faulty gaskets

Complementary Modification:

Replace valley pan and coolant pipe

The BMW 8-cylinder engine in E60 cars (N62 or N62TU engine) is equipped with an intake manifold with variable intake runners. Adjustments to the length of the intake runners is carried out by the engine control module (ECM). The ECM calculates optimum manifold runner efficiency based on ambient air temperature, engine speed, load and driver input. Intake runner length is controlled using a 12-volt drive motor with worm gears. A potentiometer is integrated with the drive motor in order to supply the ECM with feedback regarding intake manifold position. If the drive unit or another part of the system fails, the ECM locks the intake manifold runner length at a predetermined "limp-home" position and stores a fault code. A significant loss of power may be noticed by the driver if this happens.

The 8-cylinder engine utilizes metal gaskets for the intake manifold. Over time the gaskets fail and leaks develop. If you have a hard-to-find vacuum leak, replace your intake manifold gaskets. If you find oil inside your intake manifold, replace the crankcase breather valve. Clean the inside of the intake manifold thoroughly and be careful not to get any debris inside the cylinder head during the procedure. Removing the intake manifold will also give you easy access to the engine valley pan, knock sensors and coolant pipe.

When preparing to remove your intake manifold, be sure to have all the correct parts on hand and leave enough time in the day. I suggest plan for 1/2 a day. Also, be sure to have an assistant available to help lift the intake manifold out of the engine bay. The secondary air pipes are under the intake manifold. Nine out of ten times when removing the intake manifold these hoses break, so be sure to have replacements on hand.

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches.

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If you're working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Never work on your vehicle if you feel the task is beyond your ability.

Vehicle models change and evolve as they grow older, so the vehicle shown in our illustrations may vary slightly from yours. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

In this tech article, I will go over how to replace the intake manifold (green arrow) on an N62 8-cylinder engine.
Figure 1

In this tech article, I will go over how to replace the intake manifold (green arrow) on an N62 8-cylinder engine. Drain the cooling system. See our tech article on cooling system draining and filling. Remove the radiator cooling fan. See our tech article on radiator cooling fan replacing. Remove the cabin microfilter housing. See our tech article on engine covers removing.

Working at the intake air duct, pull the vacuum line (green arrow) off the air duct.
Figure 2

Working at the intake air duct, pull the vacuum line (green arrow) off the air duct.

Using a flathead screwdriver, loosen both the intake air duct hose clamps (green arrows).
Figure 3

Using a flathead screwdriver, loosen both the intake air duct hose clamps (green arrows).

Once the clamps are loose, pull the air duct off the throttle housing.
Figure 4

Once the clamps are loose, pull the air duct off the throttle housing. Then pull it off the intake air box. Place the duct aside.

Working at the front of the intake manifold, squeeze the collar (green arrows) while pulling the hose off the intake manifold.
Figure 5

Working at the front of the intake manifold, squeeze the collar (green arrows) while pulling the hose off the intake manifold.

Follow the hose to the right side valve cover.
Figure 6

Follow the hose to the right side valve cover. Squeeze the collar while pulling the hose (green arrow) off the valve cover.

Next, remove the purge solenoid (yellow arrow) hose from the intake manifold.
Figure 7

Next, remove the purge solenoid (yellow arrow) hose from the intake manifold. Squeeze the collar while pulling the hose (green arrow) off the intake manifold.

Then pull the purge solenoid off the mounting bracket (yellow arrow) in the direction of the green arrow.
Figure 8

Then pull the purge solenoid off the mounting bracket (yellow arrow) in the direction of the green arrow.

Once the purge solenoid is removed from the bracket, detach the lower hose (yellow arrow) by squeezing the collar while pulling the hose off the valve.
Figure 9

Once the purge solenoid is removed from the bracket, detach the lower hose (yellow arrow) by squeezing the collar while pulling the hose off the valve. Then disconnect the electrical connector (green arrow) by pressing the release wire and pulling the connector off the valve.

Working at the hose on the left side valve cover, squeeze the collar while pulling the hose (green arrow) off the valve cover.
Figure 10

Working at the hose on the left side valve cover, squeeze the collar while pulling the hose (green arrow) off the valve cover.

Working at the left side of the intake manifold, pull the electrical connector (green arrow) straight out of the electrical junction.
Figure 11

Working at the left side of the intake manifold, pull the electrical connector (green arrow) straight out of the electrical junction. This will allow the hose (yellow arrow) you detached earlier to be removed from the intake manifold in the following step.

The breather hose (yellow arrow) looks like it could stay attached during removal.
Figure 12

The breather hose (yellow arrow) looks like it could stay attached during removal. However, there is a coolant hose (red arrow) that loops over the top of the breather hose (green arrow). Squeeze the collar while pulling the hose (green arrow) off the intake manifold.

Then push the coolant hose (green arrow) under the breather hose connection pipe.
Figure 13

Then push the coolant hose (green arrow) under the breather hose connection pipe.

Now we have to disconnect the upper electrical connectors and remove the electrical junction hold downs.
Figure 14

Now we have to disconnect the upper electrical connectors and remove the electrical junction hold downs. Start by removing the front electrical connector on the right side. You already disconnected the left one (blue arrows). Then disconnect the electrical connectors along the sides of the intake manifold (green arrows). You have already disconnected each style of connector here. The connector type varies. Then remove the four T30 Torx fasteners (red arrows) on top of the hold down brackets (yellow arrows). Then remove the hold down brackets from the engine.

Next up is the wiring that runs down the front of the engine.
Figure 15

Next up is the wiring that runs down the front of the engine. Start on the right side. Follow the wires (green arrow) down the front of the engine. You will be disconnecting both right side VANOS solenoids, the engine temperature sensor and A/C compressor. Then follow the left side wires (yellow arrow) down the front of the engine. You will be disconnecting both VANOS solenoids and the alternator. The alternator can be tough, depending on equipment. It does have to be disconnected, so worse case remove the alternator to make it easier. See our tech article on alternator replacing.

Remove the strut brace (yellow arrows).
Figure 16

Remove the strut brace (yellow arrows). First remove the four T45 Torx fasteners (green arrows). Then detach the battery cable (red arrow) from the brace. Remove the brace from the vehicle.

Lift the wiring junction (red arrow) up and away from the intake manifold.
Figure 17

Lift the wiring junction (red arrow) up and away from the intake manifold. Working at the back of the intake manifold, disconnect the variable intake manifold actuator (green arrow) electrical connector (yellow arrow).

Then move to the right side of the intake.
Figure 18

Then move to the right side of the intake. Lift the wiring junction up (green arrow) and disconnect the variable intake manifold actuator (green arrow) electrical connector (yellow arrow).

Lift the wiring junction (yellow arrows) up and secure it out of the way for the remainder of the procedure.
Figure 19

Lift the wiring junction (yellow arrows) up and secure it out of the way for the remainder of the procedure.

Working at the left side strut tower, remove the fuel line safety collar (blue arrow) by pulling it straight off the fuel line.
Figure 20

Working at the left side strut tower, remove the fuel line safety collar (blue arrow) by pulling it straight off the fuel line. Then push the release collar (yellow arrow) in toward the fuel line and hold it while pulling the fuel line in the direction of the red arrow.

Just out of view on the right side you can see my bungee cord (red arrow) holding the wiring junction out of the way.
Figure 21

Just out of view on the right side you can see my bungee cord (red arrow) holding the wiring junction out of the way. Working at the front of the intake manifold, pull the wire loom (yellow arrow) out of the mount and down on top of the throttle housing. When removing the intake manifold in the following step, you will have to move this loom out of the way while lifting the manifold. Remove both Valvetronic motors (blue arrows). See our tech article on Valvetronic motor replacing. Remove the ten 11mm intake manifold nuts (green arrows). Use a magnet to extract the nuts once they are removed.

With help from a friend, lift the intake manifold up to remove it, untangling wires and hoses as you both lift it.
Figure 22

With help from a friend, lift the intake manifold up to remove it, untangling wires and hoses as you both lift it.

With the intake manifold removed you can now replace the intake manifold gaskets (green arrows).
Figure 23

With the intake manifold removed you can now replace the intake manifold gaskets (green arrows). Be sure to clean the sealing surface before installing new ones. You also have access to the secondary air pipes (red arrows). The blue arrow points to a crack in the left side air pipe. I had to replace them both as they are one piece. The plastic retainers (yellow arrows) almost always break, so have them on hand if you need to remove the air pipes. Once you make repairs and install new gaskets, tighten the intake manifold fasteners. The torque specs for the fasteners are as follows - M6 fasteners: 10Nm (7 ft-lb), M7 fasteners: 15Nm (11 ft-lb), M8 fasteners: 22 Nm (16 ft-lb). Reassemble the intake components in the reverse order of removal. Be sure all hoses and electrical connectors are routed as they were when removed.

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Comments and Suggestions:
randy Comments: hi, im having problem with increased emission, what can cause it? i have bmw 545i 2005

thank you
September 5, 2016
  Followup from the Pelican Staff: An engine misfire can. - Nick at Pelican Parts  
Alex Comments: I need to replace the knock sensors. So, I really am just looking to lift the manifold. Do the gaskets always have to be replaced?
August 30, 2016
  Followup from the Pelican Staff: Yes, they have to be replaced. - Nick at Pelican Parts  
JD Comments: What is the torque requirement for 11MM intake nuts?
July 22, 2016
  Followup from the Pelican Staff: I don’t have that info.

I would grab a repair manual. It will have the procedure, special tools and torque specs.

Give our parts specialists a call at 1-888-280-7799. - Nick at Pelican Parts
 
Rob Comments: Hi great right up. FYI though, I was able to remove and reinstall the intake manifold without disconnecting the connection to the alternator and another on the passengers side that ran down to the AC I think. It made the job much faster. Thanks!
June 3, 2016
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 

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Page last updated: Sun 12/11/2016 02:23:08 AM