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214 Posts
Got the headers a while back from a fellow CF member, who was selling his truck, and just now got around to installing these SOBs.
First off, it's not a hard job really, just frustrating because unless the truck is on a proper lift, you're always at a funny angle working in a tight spot. If it's your first time, give yourself plenty of time and try to be patient.
Other supplies:
Ratchet set (of course)
2-6: 10MM 1.5 Bolts w/matching washers and nuts (I used 3 on the driver's side because the header and cat did not align correctly, and 1 on the passenger side because it did align correctly)
2: Header to Cat Gasket - Nissan Part No. 20691-30P00 - $8.91 each (optional)
Bucket of curse words
Getting started:
1) Get your truck up on a stand and remove the wheels and wheel well.
![]()
2) Get under the truck and unbolt the exhaust. There are three locations where the exhaust is bolted to the truck. Go find them.
3) Unbolt the exhaust from the first Cat on both the driver and passenger side.
![]()
4) Pull the exhaust back a few inches so it's no longer connected to the cat.
Driver's Side:
5) Remove the O2 sensor from the cat. I forgot to do this and it was just one more little annoyance that I had to deal with later as the cat flapped around while I tried to take out the sensor.
6) You can look through the wheel well and see the heat shield. Remove the three bolts that are there. Two on top and one toward the bottom. I broke a head or two, but it doesn't matter because they are connected to the manifold, and you're going to throw that away anyway.
![]()
7) Once you unbolt everything, the heat shield can be removed. You don't have to be too gentle. Just bend and push things out of the way till it's out. Just don't pop those hoses off...
![]()
8) Now, you have complete access to the manifold. I found that a deep socket with a 3 inch extension seemed to fit in there best and let me do the job. If you're luck enough to have a long extension and all that, go for it... more power to you.
9) Removing the bolts for the first time is a pain in arse. Just get in there and spray it down with whatever you got WD40 or any of those. It'll take some elbow grease and cuss words to get 'em off.
![]()
10) Now the header and cat slide out toward the back of the truck. The cat has two bolts with star drivers on it. Can someone tell me what these things are actually called? Anyway, take the two pieces apart.
**Don't lose or mess up your gasket between the engine and manifold/header. You reuse it. Clean it off and stick it back up in there.**
11) Put the new header and cat together. Like I said earlier, my driver's side didn't line up right; so, I had to take all their stuff off and replace them with three bolts. 10 MM with 1.5 threading.
![]()
Ain't is purrrrty?
![]()
12) Slide the header and cat back into place and start reattaching all your gear. Throw some anti-seize on there, and tighten the bolts nice and good.
![]()
**Reconnect the O2 sensor to the cat**
Passenger Side:
You don't need to lift the engine and all that BS.
The passenger side was a bit more tough because it's angled downward more and you can't get torque on the nuts from the top like you could the driver's side, but it's manageable.
13) Ended up cutting out the heat shield on this side because there is less room to work with. Not going to use it anyway; so, what does it matter to get some metal shears and go to town.
![]()
14) Now you have access to the manifold and you can go to town like you did the other side. Good luck!
![]()
15) Get the manifold off like the other side. My passenger wheel well is still on in this pic because the next day, I was working with a buddy who has a shop and we decided not to take the wheel well off again. No, it's not a two day job, but I started late the first day and had other things to do. You can do this in one day easily. Working in the shop the second day definitely beat being on the ground the first day.
![]()
16) I had some leakage in between the header and cat; so, I took off the old gaskets and replaced them with new ones. Some people might not need to do this, but I thought it was necessary for my application. The gaskets are just little rings that go over the cat end.
![]()
17) Attach the header back in place. Don't forget the gasket between the engine and header.
![]()
**Reconnect the O2 sensor to the cat**
Finishing up:
18) Reconnect the exhaust to the cats.
![]()
19) Hook your exhaust back up in the three locations.
![]()
20) Double check all your bolts so that everything is tight.
I think that's about it. Just like any first time (except for sex) it takes longer than you would expect, but now that I've done it, it wouldn't take nearly as long.
Leakage note: you'll know you have a leak because you can hear this whisping sound that seems to putter with the engine. Just put your head near the wheel well and rev the engine a bit, you'll hear it. I had that; so, I got the gaskets from the local Nissan dealership. They usually have them in stock.
I'll try to get some sound clips later.
First off, it's not a hard job really, just frustrating because unless the truck is on a proper lift, you're always at a funny angle working in a tight spot. If it's your first time, give yourself plenty of time and try to be patient.
Other supplies:
Ratchet set (of course)
2-6: 10MM 1.5 Bolts w/matching washers and nuts (I used 3 on the driver's side because the header and cat did not align correctly, and 1 on the passenger side because it did align correctly)
2: Header to Cat Gasket - Nissan Part No. 20691-30P00 - $8.91 each (optional)
Bucket of curse words
Getting started:
1) Get your truck up on a stand and remove the wheels and wheel well.
2) Get under the truck and unbolt the exhaust. There are three locations where the exhaust is bolted to the truck. Go find them.
3) Unbolt the exhaust from the first Cat on both the driver and passenger side.
4) Pull the exhaust back a few inches so it's no longer connected to the cat.
Driver's Side:
5) Remove the O2 sensor from the cat. I forgot to do this and it was just one more little annoyance that I had to deal with later as the cat flapped around while I tried to take out the sensor.
6) You can look through the wheel well and see the heat shield. Remove the three bolts that are there. Two on top and one toward the bottom. I broke a head or two, but it doesn't matter because they are connected to the manifold, and you're going to throw that away anyway.
7) Once you unbolt everything, the heat shield can be removed. You don't have to be too gentle. Just bend and push things out of the way till it's out. Just don't pop those hoses off...
8) Now, you have complete access to the manifold. I found that a deep socket with a 3 inch extension seemed to fit in there best and let me do the job. If you're luck enough to have a long extension and all that, go for it... more power to you.
9) Removing the bolts for the first time is a pain in arse. Just get in there and spray it down with whatever you got WD40 or any of those. It'll take some elbow grease and cuss words to get 'em off.
10) Now the header and cat slide out toward the back of the truck. The cat has two bolts with star drivers on it. Can someone tell me what these things are actually called? Anyway, take the two pieces apart.
**Don't lose or mess up your gasket between the engine and manifold/header. You reuse it. Clean it off and stick it back up in there.**
11) Put the new header and cat together. Like I said earlier, my driver's side didn't line up right; so, I had to take all their stuff off and replace them with three bolts. 10 MM with 1.5 threading.
Ain't is purrrrty?
12) Slide the header and cat back into place and start reattaching all your gear. Throw some anti-seize on there, and tighten the bolts nice and good.
**Reconnect the O2 sensor to the cat**
Passenger Side:
You don't need to lift the engine and all that BS.
The passenger side was a bit more tough because it's angled downward more and you can't get torque on the nuts from the top like you could the driver's side, but it's manageable.
13) Ended up cutting out the heat shield on this side because there is less room to work with. Not going to use it anyway; so, what does it matter to get some metal shears and go to town.
14) Now you have access to the manifold and you can go to town like you did the other side. Good luck!
15) Get the manifold off like the other side. My passenger wheel well is still on in this pic because the next day, I was working with a buddy who has a shop and we decided not to take the wheel well off again. No, it's not a two day job, but I started late the first day and had other things to do. You can do this in one day easily. Working in the shop the second day definitely beat being on the ground the first day.
16) I had some leakage in between the header and cat; so, I took off the old gaskets and replaced them with new ones. Some people might not need to do this, but I thought it was necessary for my application. The gaskets are just little rings that go over the cat end.
17) Attach the header back in place. Don't forget the gasket between the engine and header.
**Reconnect the O2 sensor to the cat**
Finishing up:
18) Reconnect the exhaust to the cats.
19) Hook your exhaust back up in the three locations.
20) Double check all your bolts so that everything is tight.
I think that's about it. Just like any first time (except for sex) it takes longer than you would expect, but now that I've done it, it wouldn't take nearly as long.
Leakage note: you'll know you have a leak because you can hear this whisping sound that seems to putter with the engine. Just put your head near the wheel well and rev the engine a bit, you'll hear it. I had that; so, I got the gaskets from the local Nissan dealership. They usually have them in stock.
I'll try to get some sound clips later.
