What… A… Job… BUT, man does it feel amazing to have this fixed
I had “the tick” on the drivers side and it was starting to drive me batty, so I decided I had to do something. I researched the DT Headers, and while it appears they are CARB legal now, it wasn’t easy to find them, and I also didn't want to be the first guy to roll up to the Smog check shop and have them freak out. I was also was nervous about the installation given some of the comments in this GREAT thread:
LX470/100 Series Doug Thorley Headers Install Tips, Tricks, Lessons, Parts List, and Tools - https://forum.ih8mud.com/threads/lx470-100-series-doug-thorley-headers-install-tips-tricks-lessons-parts-list-and-tools.1255049/
Given this, I decided to stick with stock. And even if you decide to stick with OEM like I do, still go read that thread. Tons of excellent advice in there. I almost posted in that thread, but wanted to start one for those looking to stick with OEM manifolds given there are some differences with the DT install.
The Rig
2001 LX470 with 250k miles. Sunbelt car (TX & CA) with only small amounts of surface rust. (Yes I know, I’m lucky) But the AHC being in the way makes this tougher.
Cat Pipe:
Started with this, and got nervous right away because two of the studs that connect the manifold to the cat pipe snapped off when removing. (but at least they came off) And then I tried to take off the bolts where the cat pipe connects to the crossover pipe. And those rounded right off. Thankfully I had a rotary tool with a cutoff wheel, and that did the trick and I cut those suckers off.
Motor Mounts
After reading about this job, and seeing I needed to loosen these to raise the engine, I then found this thread (Motor mounts - https://forum.ih8mud.com/threads/motor-mounts.685374/page-8) where many people are reporting good experiences after replacing them. So given that, this seemed like a great “while you are in there” type of job. So I bought new mounts, and when changing out the manifold I just took the old mount completely out. This of course gives you a touch more room. Not sure why no one mentions this, but this does indeed seem like a great time to change these out.
Steering Shaft and Dipstick
I did not take these loose. I could see how it might give you more room, but I think not necessary if you don’t want to deal with it.
Heat Shield
This seems like a simple thing, but was hard to figure out. Once you unbolt it, all you want to do is take it out of the way, but that is easier said than done. Yes you can get it out, but it might take you 30 min to figure out. Or just leave it loose and take it out when you take out the manifold. The same problem happens when you put the new manifold in. I rolled the dice and put in the new manifold at first without the shield. This made the manifold installation much nicer, but then I had to mess around for 30 min to try and figure out how to get the heat shield in.
The Main Event - Manifold Nuts
Man this gets intimidating really quick. The first few top nuts aren’t too bad, but then you are getting into crazy angles with nuts you can barely see. Just do your best to try and make sure the socket is on flush when you get ready to try and loosen. Being a sunbelt car I ended up getting pretty lucky. I was able to get all manifold nuts off without any rounded off/stuck nuts. (Which surprised me given the cat pipe bolts needed cutting off) And of course PB-blast these things even if it is only a few hours before. I forgot to spray one of the nuts, and of course that was the one I tried to do with my impact. The good news is the nut did come off, but it cracked the socket in two places. :O The other nuts that had been sprayed were easier.
Head to Manifold Studs
Even though I bought all new head studs, I didn’t use any of them. After spraying down the old studs and working a nut on and off a few times, they all felt pretty good. I was also nervous about screwing something up when taking out the old studs in such a tight space, so I didn’t even bother. I’m not sure if this was the best choice, but I see in most of the posts this is what everyone else does as well. (For the three studs that connect the manifold to the cat pipe I of course did replace those with new)
Re-install
Strangely enough, this was somewhat easy? I did this the next day and with more patience I was able to find better angles and in this case using an all ⅜” drive setup worked much better to get good angles on the nuts. I was actually able to get all of them from the wheel well. I took a picture of the magic setup. Ratchet, to 6” regular extension to 6” wobble extension, to Universal Impact Joint, to deep wheel 14mm.
Tools
Parts List
I got all new bolts and gaskets for all the pipes I was planning to touch
The culprit:
Old vs new:
All cleaned up ready for new:
The "magic" setup: Ratchet, to 6” regular extension to 6” wobble extension, to Universal Impact Joint, to deep wheel 14mm.
Got Tools?
I had “the tick” on the drivers side and it was starting to drive me batty, so I decided I had to do something. I researched the DT Headers, and while it appears they are CARB legal now, it wasn’t easy to find them, and I also didn't want to be the first guy to roll up to the Smog check shop and have them freak out. I was also was nervous about the installation given some of the comments in this GREAT thread:
LX470/100 Series Doug Thorley Headers Install Tips, Tricks, Lessons, Parts List, and Tools - https://forum.ih8mud.com/threads/lx470-100-series-doug-thorley-headers-install-tips-tricks-lessons-parts-list-and-tools.1255049/
Given this, I decided to stick with stock. And even if you decide to stick with OEM like I do, still go read that thread. Tons of excellent advice in there. I almost posted in that thread, but wanted to start one for those looking to stick with OEM manifolds given there are some differences with the DT install.
The Rig
2001 LX470 with 250k miles. Sunbelt car (TX & CA) with only small amounts of surface rust. (Yes I know, I’m lucky) But the AHC being in the way makes this tougher.
Cat Pipe:
Started with this, and got nervous right away because two of the studs that connect the manifold to the cat pipe snapped off when removing. (but at least they came off) And then I tried to take off the bolts where the cat pipe connects to the crossover pipe. And those rounded right off. Thankfully I had a rotary tool with a cutoff wheel, and that did the trick and I cut those suckers off.
Motor Mounts
After reading about this job, and seeing I needed to loosen these to raise the engine, I then found this thread (Motor mounts - https://forum.ih8mud.com/threads/motor-mounts.685374/page-8) where many people are reporting good experiences after replacing them. So given that, this seemed like a great “while you are in there” type of job. So I bought new mounts, and when changing out the manifold I just took the old mount completely out. This of course gives you a touch more room. Not sure why no one mentions this, but this does indeed seem like a great time to change these out.
Steering Shaft and Dipstick
I did not take these loose. I could see how it might give you more room, but I think not necessary if you don’t want to deal with it.
Heat Shield
This seems like a simple thing, but was hard to figure out. Once you unbolt it, all you want to do is take it out of the way, but that is easier said than done. Yes you can get it out, but it might take you 30 min to figure out. Or just leave it loose and take it out when you take out the manifold. The same problem happens when you put the new manifold in. I rolled the dice and put in the new manifold at first without the shield. This made the manifold installation much nicer, but then I had to mess around for 30 min to try and figure out how to get the heat shield in.
The Main Event - Manifold Nuts
Man this gets intimidating really quick. The first few top nuts aren’t too bad, but then you are getting into crazy angles with nuts you can barely see. Just do your best to try and make sure the socket is on flush when you get ready to try and loosen. Being a sunbelt car I ended up getting pretty lucky. I was able to get all manifold nuts off without any rounded off/stuck nuts. (Which surprised me given the cat pipe bolts needed cutting off) And of course PB-blast these things even if it is only a few hours before. I forgot to spray one of the nuts, and of course that was the one I tried to do with my impact. The good news is the nut did come off, but it cracked the socket in two places. :O The other nuts that had been sprayed were easier.
Head to Manifold Studs
Even though I bought all new head studs, I didn’t use any of them. After spraying down the old studs and working a nut on and off a few times, they all felt pretty good. I was also nervous about screwing something up when taking out the old studs in such a tight space, so I didn’t even bother. I’m not sure if this was the best choice, but I see in most of the posts this is what everyone else does as well. (For the three studs that connect the manifold to the cat pipe I of course did replace those with new)
Re-install
Strangely enough, this was somewhat easy? I did this the next day and with more patience I was able to find better angles and in this case using an all ⅜” drive setup worked much better to get good angles on the nuts. I was actually able to get all of them from the wheel well. I took a picture of the magic setup. Ratchet, to 6” regular extension to 6” wobble extension, to Universal Impact Joint, to deep wheel 14mm.
Tools
- There is a good chance you are going to need some brute force method in case you run into tricky rusted exhaust bolts. A cutoff wheel did the trick for me.
- I personally found that “normal” universal joints were too “wobbly.” I found that “Universal Impact Joints” worked much better for me (Like these: Amazon product ASIN B0CB12QP9Y )
- I also found out after I did this job that they make “Flex Head Deep Impact Socket” sets. Knowing what I know now I probably would have pulled the trigger on these as they look a little less bulky compared to the ones above.
- Sometimes I used a 1/2" setup to crack these, and other times I used a 3/8" setup. This will probably depend on the tools you already have, but for some of these a ½ setup with a breaker will probably be needed.
- To Impact or to not Impact? This seems to be debated on the internet. Some claim it is actually helpful, others claim it just rounds nuts and snaps studs. I tried it on a few, and it did work, but you are always kind of nervous you might just round them off. Still not sure what the right answer is here.
- As has already been mentioned by many others, make sure you have a variety of extensions. I also purchased some wobble extensions that worked well.
- And yes, ratcheting wrenches also help!
Parts List
I got all new bolts and gaskets for all the pipes I was planning to touch
| Exhaust Tick Parts (for 2001 MY) | P/N | Qty | Notes | |
| Drivers Side Exhaust Manifold | 17105-50121 | $241.60 | 1 | |
| GASKET, EXHAUST MANIFOLD TO HEAD | 17173-50021 | $16.36 | 1 | |
| STUD (FOR EXHAUST MANIFOLD TO CYLINDER HEAD) | 90126-10015 | $2.06 | 8 | |
| Nut for Manifold Stud | 90179-10070 | $1.04 | 8 | FSM says torque to 32 ft/lbs |
| Heat Shield Bolts | 91621-J0612 | $0.57 | 4 | |
| Manifold to cat pipe studs | 90126-10006 | $3.65 | 3 | |
| Manifold to cat pipe nuts | 90179-10070 | $1.04 | 3 | FSM says torque to 46 ft/lbs |
| Manifold to cat pipe Gasket | 90917-06065 | $3.55 | 1 | |
| Drivers cat pipe to crossover pipe Gasket | 90917-06045 | $1.28 | 1 | |
| Drivers cat pipe to crossover pipe bolt | 91515-61035 | $0.69 | 2 | |
| Drivers cat pipe to crossover pipe nut | 94185-61000 | $0.75 | 2 | FSM says torque to 30 ft/lbs |
| Upstream O2 sensor in manifold | Denso 234-4169 | $45.00 | 2 | |
| Tools | ||||
| Star Drive Sockets for the studs - e10 inverted torx | $5.00 | 1 | ||
| 1/2 Drive 14mm Socket "mid" size. Not deep, but deep enough for stud | $8.00 | 1 | ||
| Metric Flex-Head Ratcheting Wrenches | Pittsburgh Set | $30.00 | 1 | |
| Flex Joints - PITTSBURGH PRO Universal Impact Joint Set | $9.00 | 1 | ||
| Lots of 3/8 extensions, including a few wobble extensions. | Pittsburgh Set | $20.00 | 1 | |
| Oxygen sensor “tool” or a 23mm flex head ratcheting wrench | $8.00 | 1 | ||
| Optional? - Spiral Type Deep Extractor | $26.00 | 1 | ||
| Engine/Trans Mounts (for 2001 MY) | ||||
| Drivers Side Engine Mount | 1236150121 | $106.63 | 1 | FSM says torque side bolts to 22 ft/lbs. No spec for top nut |
| Passenger Side Engine Mount | 1236150121 | $106.63 | 1 | FSM says torque side bolts to 22 ft/lbs. No spec for top nut |
| Trans Mount | 1237150081 | $65.60 | 1 |
The culprit:
Old vs new:
All cleaned up ready for new:
The "magic" setup: Ratchet, to 6” regular extension to 6” wobble extension, to Universal Impact Joint, to deep wheel 14mm.
Got Tools?
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