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This is a How-To for replacing the passenger side Exhaust Manifold in a 2001 Xterra 3.3L. I don't know how this varies from year-to-year so please let me know if everything was the same for your year and I'll add it to the applicable years. Hopefully you'll find this useful as I know this is a systemic issue with at least 2000 and 2001 Xterras. Plus I hated the puffing noise caused by the crack. It was worth the effort just not not hear that anymore.




Tools:

Required:
Standard set of shallow and deep sockets (9-17mm)
3/8" drive, 1/2" drive preferred for better leverage
6" extension
Torque Wrench
Jack, Jack Stands
PB Blaster
Time ~ 4hrs
Beer

Optional:
Deadblow/Cheater
Metal Bristle brush
Another 6" extension or a single longer one

Resources:
Shop Repair Manual (using the search tool in this forum will lead you to it)
http://www.enginebuildermag.com/Article/59263/19992001_frontier_and_xterra_righthand_exhaust_manifolds_cracked_in_vgs33e_engines.aspx

Parts:
I bought my passenger side exhaust manifold from Advanced Auto Parts for around $80. It came with the cast manifold, the seal for between the manifold and the block, as well as the seal between the exhaust manifold and the first exhaust pipe. As for hardware, it came with three (3) double threaded bolts and associated nuts which were meant for the connection between the exhaust manifold and the exhaust pipe. I didn't end up using these, mostly because the bolts stayed attached and I didn't feel like trying to remove them, nor did I think I had the appropriate star shaped socket (not bit).

As I mention in my writeup, I removed two nuts for a flange further down on the exhaust system to get enough room to reach the exhaust manifold bolts. This flange also has a seal that should probably be replaced (thoughts?). I didn't anticipate on unbolting this so I personally didn't replace mine. Replace or don't at your own risk.

Preparation:
The most involved mod I've done so far is the 2" BL. I learned very quickly how valuable preparation work was, specifically the liberal application of PB Blaster in advance. I attempted to apply that practice before undertaking this mod (especially not having a How-To) but failed miserably because I didn't spray any of the exhaust or take off the heat shield to spray the primary exhaust manifold bolts.

1. At the very minimum spray the three (3) bolts that hold the heat shield to the exhaust manifold (Figure 1). *NOTE: Do not be alarmed when the engine starts smoking, it's just the PB Blaster cooking off. I recommend letting the PB soak a while before starting the engine to allow the capillary action time to work.

2. Spray the two bolts at the exhaust flange (Figure 5). I recommend also scraping off any of the excess rust to let the PB blaster work better. either with something like a screwdriver, knife or even better a metal bristle brush.

3. A couple days of PB later, try and remove the heat shield to spray the exhaust manifold bolts (Figure 8). This step isn't necessary, or very fun, but I do recommend it if you don't have an impact wrench. Be sure to replace the heat shield if you plan on starting your X - don't want any melted hoses etc.

Manifold Replacement:

1. Jack up the front passenger side and remove the wheel. *MAKE SURE TO USE JACK STANDS AND DO THIS PROPERLY OR SERIOUS INJURY OR DEATH CAN RESULT*

2. Remove the three (3) bolts holding the exhaust manifold heat shield. Make sure to leave the ground cable/strap in tact.

Figure 1: Heat Shield Bolts

3. Remove the two (2) bolts/screws holding the bracket for the power steering and coolant(?) lines. This will create more room for the following step.

Figure 2: Space Making 1

4. Remove another bolted bracket to help create more room

Figure 3: Space Making 2

5. Remove the heat shield. I had the 2" BL so this was relatively easy with a bit of trail and error. Others might have some difficulty.

6. Disconnect and detach completely the two sensors cables to allow for more movement of the exhaust pipes. As with any clips on the X, remain calm in order to correctly unclip them. Something to do with yin and yang...

Figure 4: Sensors already disconnected and detached

7. Remove the two (2) nuts. I believe these are 16mm nuts but I ended up using a 17mm socket because they were too corroded. Mine rounded off the edges pretty badly, that's why I mentioned the need to clean these two nuts. This is the point where I started using a deadblow (priceless!). A cheater would also be usefull if you can find one small enough. If you don't live in a cold/salty climate this will probably be much easier.

Figure 5: Blurry pic of exhaust flange

8. Remove the bolt for the virbration dampening mount near the flexible portion of the exhaust.

Figure 6: Exhaust Mount Bolt

9. Remove the three (3) nuts attaching the exhaust manifold to the rest of the exhaust.

Figure 7: Removing exhaust connection bolts

10. Disconnect the exhaust from the manifold and overlap the two exhaust flanges disconnected in step 4 so you can slide/wiggle the exhaust more towards the rear of the vehicle to allow enough clearance to get to the manifold bolts. *BE CAREFUL NOT TO CUT/DAMAGE THE SENSOR WIRES ON SHARP HEAT SHIELDS*

11. Remove the six (6) nuts holding the exhaust manifold to the block. I had 3 that removed only the nut and 3 that removed the nut and bolt together. Not sure this really makes a difference.

Figure 8: Exhaust manifold bolting (can't see 1 bolt)


Figure 9: Exhaust manifold removed

12. Mount the SOB on the wall. I brought mine to work as show and tell.

13. Reverse the removal procedure. Make sure to replace the seals with the
ones provided in the kit.

14. Torque the six (6) exhaust manifold bolts to 48 ft-lb. Torque the three (3) bolts that connect the manifold to the downstream exhaust to 30-37 ft-lb.

15. When installing the new heat shield I had to bend about a 1/2" deep, 1.5" long section to create clearance from a bolt. I also ended up using my deadblow to get all of the holes to line up. Be careful because I popped a spot weld.

Figure 10: Bending new heat shield

Good luck!!!
 

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well done man. rep points given!
 

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Great write up. I think I have this happening on the drivers side.
This will be a great help!

Points Awarded!
 

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question: so you didn't replace the studs going to the engine?

This is the part that every mechanic mentions to be a problem, because you probably have to torch it. But if you can just reuse the old studs, then i will do that.

Is there any potential problems with using old studs?

Marc
 

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Discussion Starter #9
question: so you didn't replace the studs going to the engine?
I didn't replace the studs that connect the exhaust manifold to the engine. I even had bought new studs, but because a few of the old nuts didn't come off of the studs (didn't know to buy nuts) I didn't replace them. Not to mention some of the studs stayed in the block. This is where I'm guessing where torching would come in.

Is there any potential problems with using old studs?
I have no idea. Hopefully another more veteran member of the forum (mechanic too?) will be able to answer this question. All I know is that it's going strong for a couple weeks now and ff I hear any puffing like the cracked exhaust I'll know exactly where to look first.

Please post back here if you find anymore info about this. I'd be interested even if I had to open it back up and replace 'em.
 

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I even had bought new studs, but because a few of the old nuts didn't come off of the studs (didn't know to buy nuts) I didn't replace them. Not to mention some of the studs stayed in the block. This is where I'm guessing where torching would come in.
So no studs came out of the block for you? Also, i didn't believe that there were nuts that go block>stud>nut.

I thought it was just block>stud>exhaust manifold>nut

What worries me is trying to remove one of these studs, and then it breaks==screwed!

Marc
 

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So no studs came out of the block for you? Also, i didn't believe that there were nuts that go block>stud>nut.

I thought it was just block>stud>exhaust manifold>nut

What worries me is trying to remove one of these studs, and then it breaks==screwed!

Marc
Another question:

i look at the passenger side exhaust manifold and i see a ground wire coming from the manifold intact. I look at the drivers side and i see another ground wire, but it is not intact (broken). What is this ground for and should i replace the driver's side? And where do i get this wire?

Marc
 

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Discussion Starter #13 (Edited)
So no studs came out of the block for you? Also, i didn't believe that there were nuts that go block>stud>nut.

I thought it was just block>stud>exhaust manifold>nut

What worries me is trying to remove one of these studs, and then it breaks==screwed!
The studs are threaded on both ends. One end threads into the block, the exahust manifold is in the middle (no thread) and the nut is on the other end of threads. As you can see in the picture of the exhaust manifold removed in the original post, 3 of the studs remained in the block. The nut stayed attached to the other 3 studs that were removed. I hope this clarifies.


Another question:

i look at the passenger side exhaust manifold and i see a ground wire coming from the manifold intact. I look at the drivers side and i see another ground wire, but it is not intact (broken). What is this ground for and should i replace the driver's side? And where do i get this wire?
I must say you ask some interesting and tough questions. I didn't know the answer to this one off of the top of my head. I assumed it had something to do with making sure there wasn't static/charge on the exhaust if there was any that wasn't fully combusted.

I did a little searching and found an aftermarket product that gives a little description at the function of the ground cable. (take it with a grain of salt of course)

"Universal Hot Earth Exhaust Ground System for cars, trucks and SUVs Features:
- Increase torque response
- Reduced static electricity in exhaust
- Reduced vibration noise from exhaust"
http://www.racinglab.com/hoteaexgrsy.html

I also looked at http://www.nissanparts.cc but couldn't find it in the exhuast manifold section. It might be worth taking a look around in there. For how easy it is, I think it's worth replacing if you could find generic one at a local auto store for $5-10.
 

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Nice write up! It does make it much easier that you have a body lift in that there is more room between the inner fender well and the frame. It gives you more room to work in.

So no studs came out of the block for you? Also, i didn't believe that there were nuts that go block>stud>nut.

I thought it was just block>stud>exhaust manifold>nut

What worries me is trying to remove one of these studs, and then it breaks==screwed!
Marc
The studs go into the block, then the exhaust manifold gasket, then the manifold and then the studs. When putting studs into the block, torque is very important since the stud stretches with torque. Since the block and manifold have great changes in temperature, there is a lot of expansion and contraction, which the torque helps accommodate. Not enough, the may loosen, too much they may break. With a little heat from a torch, the come out fairly well most of the time, even in high salt areas. Normally, it's best to replace them, but probably fine with the old ones.

Another question:

i look at the passenger side exhaust manifold and i see a ground wire coming from the manifold intact. I look at the drivers side and i see another ground wire, but it is not intact (broken). What is this ground for and should i replace the driver's side? And where do i get this wire?
Marc
Since there are many sensors on the engine, that ground strap is important. Your ECU is just a glorified volt meter. Each of those sensors send voltage to the ECU. Mostly very small voltages. Without the proper ground, resistance can be increased which could change the line voltage sent to the ECU. You can pick up a ground strap at any auto parts store.
 

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So I replaced the driver's side exhaust manifold Saturday...all i have to say is WOW!

My car sounds brand new! Luckily none of the studs broke off and the job took me only 5 hours. The worst part was just trying to fit your hands inside the small area. Also there are a bunch of parts that just get in the way. Not too hard of a job, just a lot of swearing. Patience required for this one.

So once I unbolted the old exhaust manifold it actually just fell apart! The crack was soo bad it was split into two pieces.

Word of advice: get the wrench ratchets or whatever they are called. Definitely can't do the job without it. I used a propane torch to heat the nuts of a bit and then sprayed some pbblaster in there. After unbolting the manifold, pull out from the top (hood). You need to remove one hose and a bracket to get this done. I don't believe it is possible to remove from wheel well.

Thanks for the advice guys and good luck on all your projects!
 

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Discussion Starter #19
My car sounds brand new!
I'm glad you had similar results. As I mentioned before, it was worth the time, effort and cost for me just to not hear that damn ticking anymore.

So once I unbolted the old exhaust manifold it actually just fell apart! The crack was soo bad it was split into two pieces.
Holy splitting exhaust batman! That's insane that it just fell apart. If I chucked mine on the ground though, I'm sure it would split apart. How is this not considered a recall and covered under some warranty?

I used a propane torch to heat the nuts of a bit and then sprayed some pbblaster in there. After unbolting the manifold, pull out from the top (hood). You need to remove one hose and a bracket to get this done. I don't believe it is possible to remove from wheel well.
How long did you heat the bolts? Like 30 seconds each? I'm just asking for future benefit of others. Also, did you apply any heat when reinstalling the bolts? (Sometimes required to achieve a certain thread engagement)

After unbolting the manifold, pull out from the top (hood). You need to remove one hose and a bracket to get this done. I don't believe it is possible to remove from wheel well.
I found it much easier to remove the manifold from the wheel well, but as I mentioned earlier, I have a BL so that changes things. Good to know you can remove it from above though.

Thanks for the advice guys and good luck on all your projects!
Your welcome!
 

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I probably heat the nuts for about 1-2 minutes each. I sprayed pb on them prior to heating, then heat, then sprayed pb again. I heated it enough so I could see the PB blaster smoking. I didn't get the nuts to be "red" hot because i was just too impatient.

A couple of the nuts actually didn't come off, instead, the stud actually unscrewed from the block. So i just left the nut on the stud and reinstalled after putting the new exhaust manifold on.

I don't have a BL, so that is probably why I couldn't remove it. 2 " more and I probably could have removed from wheel well.

I still have to install the ground wire though. Haven't had a chance to pick one up yet.

Now that this is done, I can get to actually improving my ride with acutal mods, no more fixing shi* anymore :)
 
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