There’s quite a few reasons for wanting to remove a VQ35 intake manifold, from installing an intake plenum spacer to servicing your knock sensor. Today we’ll be showing you how to remove the intake manifold from your Nissan V6 from start to finish. Our test car today is a 2005 Infiniti G35, although the removal process is very similar to a Nissan 350Z as they share the same engine.
Before you begin removing your VQ35 Intake Manifold, you should allow your G35 or 350Z to cool down properly and disconnect the positive terminal on your battery.
Once you’ve got the battery disconnected, the next order of business is to undo the plastic engine cover. This cover is a half cover if you own a Nissan 350Z or a full cover if you own a Infiniti G35.
Remove the 10mm nuts to remove the engine cover and allow you access to the engine and intake manifold.
Once the engine cover is removed the next thing to do is to disconnect the VQ35 mass air flow sensor. When you have the MAF disconnected you can begin disassembling the intake system and intake piping.
The unit labeled 4 above is the power duct, which can be removed by depressing the plastic push pin. Slide out the power ducting and then unclamp the intake box.
Undo the 10mm clamps that hold the intake piping together, and your intake box is now loose. There are 3 bolts that secure the intake box to the chassis, remove them now and gently pull out the intake box.
Once that your VQ35 intake box is out, you can now disconnect the rest of the clamps that go from your MAF to the throttle body.
Now go ahead and disconnect the main vacuum hose from the intake tract of your engine.
Now finish loosening the hose clamps from the intake system, and don’t forget the sneaky 10mm bolt that holds the silencer box in place.
Now you are ready to lift the entire intake tract up and out of the engine bay. Once you have the entire unit out, go ahead and start loosening the clamps that lead to your throttle body. Because the VQ35 uses a drive-by-wire system, disconnect the throttle control actuator now from the 6 pin connector.
There’s a metric hex 10 that you must use to remove the throttle body, and if you are working on this in the car you need to remove the throttle body first. There are coolant lines to disconnect from the throttle body once you have it unbolted.
Unbolt the throttle actuator and then pull to the driver side of the vehicle, using a wrench go ahead and unclip the coolant lines from the assembly.
Now that you have the throttle body removed, you can proceed with removing the 10mm bolts that run through the top half of your intake manifold. These bolts vary in length so try to remember how they are laid out once you start taking them out.
Begin with the outer bolts first and slowly work your way around the entire intake manifold.
Unclip and disconnect all the electronic connectors on the intake manifold. These are all secured by way of a 10mm bolt.
There are several points where you can use a flathead to pry the top half of your intake plenum apart. Once you have your VQ35 intake manifold separated, be mindful of the thin intake plenum gasket underneath.
This gasket is fragile and made from metal, so make sure not to bend or damage it.
Now there’s several 12mm bolts that run through the top plenum into the lower intake runners and manifold. Remove them in order as shown below :
Now that you have the intake plenum removed from your engine, you can now turn your attention to the lower runners of your VQ35 intake manifold.
Unclip your fuel injectors and disconnect the fuel pressure regulator as well as the fuel feed line from your VQ35 fuel rail. The bolts that hold the fuel rail in place are 12mm bolts, remove these and gently pull up on the rail.
Now that you have the 12mm bolts removed, you can go ahead and slide up on the rail to remove the fuel injectors.
Take care to not lose any of the plastic fuel rail insulators located under the rail. They help space out the fuel rail from your lower plenum and hold the injectors in place.
Go ahead and undo the 12mm bolts that are on either section of the lower intake manifold plenum, and the last section to loosen is the rear water pipe. There’s a 10mm bolt that runs through the rear water pipe to the intake plenum, go ahead and remove that to dislodge and free the lower runner plenum.
Once you have the 12mm bolts removed, you can go ahead and pull off the lower runner plenum to complete the job. You are now ready to install your custom VQ35 intake manifold of choice or service the cylinder heads.
Have any questions on our guide to removing the VQ35 intake manifold? leave us a comment below and let us know!