Exhaust Manifold Replacement Walk-Through?

SSTJ

SSTJ

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I haven't found one on this forum. Do we have one yet? Anyone know of any on other forums, with pics or a vid?

Of course I will also read the FSM, but I always find that a good walk-through post brings a lot of clarity to the FSM diagrams.

Edit: Some Pro Tips from this thread are below ...
  • Preparation:
    • Put painters tape on electrical connections and label before disconnecting.
    • Can remove fender for extra room. But on 2.5s, most say there is plenty of room to work.
    • Some aftermarket manifolds come with heat shields. Remove them, or be prepared to bend and cut for fitment.
    • No special tools required, except:
      • 14mm flex socket (or 15mm in some 97s). No, a universal will not do.
      • Various socket wrench extensions: 3", 6", etc. At one point I was using two 6"s and a 3".
      • Fuel line disconnect tool. In a pinch, you can get creative with plastic tubing.
      • Maybe an angle-grinder, if your manifold requires grinding. See below in "process" for details.
    • For ideas of other jobs to tackle while you're at it, see here.

  • Process:
    • RaymondT shared the updated/revised order of torquing bolts, here. Maybe the same exists for 4.0s?
    • If you pull the fuel rail, keep up with the o-rings. Some say to change them. Or a little lube to slide back in.
    • Replacing intake manifold is delicate. If not seated properly, will cause vacuum leak and sky-high engine rpms.
    • If you find oil smeared in your intake manifold or throttle body, clean throttle as described here.
    • Most replacement manifolds require grinding to match thickness to intake manifold.
      • See here and comments above for what needs to be ground down.
      • But, difference in thickness could be due to choice of gasket? See here and here.
      • I had good luck with the Dorman, purchased through Summit. No grinding required.
      • If you do have to grind, angle grinder 4-1/2" with 1/16 cutting wheel apparently works.
    • Finally, see @PauoaTJ's notes on the process here. (Closest thing to a walk-through on this forum.)

  • Follow-Up:
    • If you get lots of smoke a few minutes after first post-install start up, see this thread.
 
Last edited:
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Nobody? I may see what I can find on Google, and post my favorite links here.
 
I have replaced one on my Daughter's 99 xj. Same motor.. Its a pain. We used fsm and a couple you tube vids. And take your time,
 
oldjeepman said:
I have replaced one on my Daughter's 99 xj. Same motor.. Its a pain. We used fsm and a couple you tube vids. And take your time,
Click to expand...

Gotcha, thanks. From the vids I've seen so far, it looks a bit tedious, but it doesn't look like it requires any very special tools. Agreed?
 
I don't have any fancy tools. Just standard jeep tools..I did paint before install with Eastwood's exhaust paint..just because..
 
I replaced mine and, I didn't remove the driver's side fender. I did a lot of it from underneath. It's not a difficult job, just needs patience, and you need to ensure that you have it seated correctly, as well as the intake manifold. Also, I just could not get a torque wrench in there, so I practiced with the torque wrench at the correct settings on some bolts on my bench, and then I did my best. Does your replacement manifold have expansion bellows?
 
glowell222 said:
I replaced mine and, I didn't remove the driver's side fender. I did a lot of it from underneath. It's not a difficult job, just needs patience, and you need to ensure that you have it seated correctly, as well as the intake manifold. Also, I just could not get a torque wrench in there, so I practiced with the torque wrench at the correct settings on some bolts on my bench, and then I did my best. Does your replacement manifold have expansion bellows?
Click to expand...

Ok thanks. Good idea with the torque wrench.

Have not yet bought the replacement manifold, but yes I plan on getting the soft/flex bellows, if that's what you mean?
 
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Replacing the intake manifold is the absolutely critical part of this job. If you are not careful and rush this part of the job so it's not seated properly it will cause a vacuum leak. That will cause sky-high engine rpms when you start the engine and the entire job will have to be done over again.
 
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SSTJ said:
Ok thanks. Good idea with the torque wrench.

Have not yet bought the replacement manifold, but yes I plan on getting the soft/flex bellows, if that's what you mean?
Click to expand...
Yes, that's what I meant. Also, just in case you didn't know, there is a specific pattern to the bolt tightening.
 
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I found that the universal adapters took up too much space. The only way to get to a couple of the bolts was with the 14mm swivel.

The universals are really nice to have in the tool box, so if you're looking for an excuse to buy more tools, GO FOR IT.
 
Yep, was wondering if they might take up too much space. OK, I will purchase the one that you linked. Thanks for the tip! It would’ve been frustrating to discover in the moment.
 
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Before I do any maintenance, I mark all the steps on a white board and track torque settings and tool sizes ... it makes it so my son and I can work in parallel and do things quickly. I scribble notes on the whiteboard and later move the notes to excel. So, since you asked for a write up, attached are my notes:

2.5L_Exhaust_Manifold.png


Also, I agree with the above posts and the importance of the flex 14mm flex socket. A normal ujoint extension does not work well on the 2.5L. I also will add that for the 2.5L a 14mm flex wrench is helpful for the two outside studs. I used Tekton WRN57114.

If you do not have them, you'll also need a grinder and flap disks (the 2.5L manifolds from China need to be ground down before we 2.5L owners can use them), as well as a fuel line disconnect tool & O2 wrench.

For the 2.5L, removing the fender is not needed, we have tons of room.

Also of note, I had a Fel-Pro gasket, but it actually looked to be of lower quality than the gasket which came with the SKP manifold:
(OEM is left, Fel-Pro is middle, SKP is on the right)
2021_05_06 18_03 Office Lens.jpg




I was pleased with the SKP manifold. Unlike all the you-tube videos showing drilling out rivets to remove the extra cover, and having to grind down a lot of material, the SKP cover was held on by normal bolts (took seconds to take off), and I only had to grind down the two ears on the corners. Very little grinding.

Here is how the SKP surface looked out of the box. As you can see in the photo the truss connecting the outer ports to the inner ports is already ground down from the manufacturer. All that was left for me was to trim excess material on the ears supporting bolts #6 & #7.

20210506_180726.jpg


I did follow @RaymondT 's revised procedure and used the spacers in the Dorman kit and the modified torque specs:
Revised procedure

There were only two things I struggled with during the replacement:
1. The old exhaust flange bolts were rusted, and I had to snap them off. But the new ones were short and so it took a while to seat the new ones deep enough to get purchase.
2. The motor mount blocked the path of removing the manifold. I had to put a jack under and move things around. If I were to do this over again, I would just take the motor mount off and replace it while in there: Loosen the transmission mount bolts and motor mount, use a jack directly under the motor mount to elevate the engine, and the manifold should slide right off & the new one back on. Then slap a new mount on as per the FSM recommendation.

There is so much room to work around the 2.5L... this really only takes a couple hours if you are organized and go right at it. Longer if you are doing it for the first time and figuring things out.


Last thing, recheck the torque settings on the bolts a few days after driving, I did have some bolts back out on mine.
 
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I just did mine today...took about 4 hours...was fairly painless and that's saying a lot for this Jeep...took a month to change the clutch with some stuck bolts. I'm just estatic I took something apart and put it all back together in the same day... didn't break anything or need to run to town for parts. Used the Banks torque tubes.

IMG_20211030_122720097.jpg
 
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PauoaTJ said:
Before I do any maintenance, I mark all the steps on a white board and track torque settings and tool sizes ... it makes it so my son and I can work in parallel and do things quickly. I scribble notes on the whiteboard and later move the notes to excel. So, since you asked for a write up, attached are my notes:

View attachment 287271

Also, I agree with the above posts and the importance of the flex 14mm flex socket. A normal ujoint extension does not work well on the 2.5L. I also will add that for the 2.5L a 14mm flex wrench is helpful for the two outside studs. I used Tekton WRN57114.

If you do not have them, you'll also need a grinder and flap disks (the 2.5L manifolds from China need to be ground down before we 2.5L owners can use them), as well as a fuel line disconnect tool & O2 wrench.

For the 2.5L, removing the fender is not needed, we have tons of room.

Also of note, I had a Fel-Pro gasket, but it actually looked to be of lower quality than the gasket which came with the SKP manifold:
(OEM is left, Fel-Pro is middle, SKP is on the right)
View attachment 287272



I was pleased with the SKP manifold. Unlike all the you-tube videos showing drilling out rivets to remove the extra cover, and having to grind down a lot of material, the SKP cover was held on by normal bolts (took seconds to take off), and I only had to grind down the two ears on the corners. Very little grinding.

Here is how the SKP surface looked out of the box. As you can see in the photo the truss connecting the outer ports to the inner ports is already ground down from the manufacturer. All that was left for me was to trim excess material on the ears supporting bolts #6 & #7.

View attachment 287273

I did follow @RaymondT 's revised procedure and used the spacers in the Dorman kit and the modified torque specs:
Revised procedure

There were only two things I struggled with during the replacement:
1. The old exhaust flange bolts were rusted, and I had to snap them off. But the new ones were short and so it took a while to seat the new ones deep enough to get purchase.
2. The motor mount blocked the path of removing the manifold. I had to put a jack under and move things around. If I were to do this over again, I would just take the motor mount off and replace it while in there: Loosen the transmission mount bolts and motor mount, use a jack directly under the motor mount to elevate the engine, and the manifold should slide right off & the new one back on. Then slap a new mount on as per the FSM recommendation.

There is so much room to work around the 2.5L... this really only takes a couple hours if you are organized and go right at it. Longer if you are doing it for the first time and figuring things out.


Last thing, recheck the torque settings on the bolts a few days after driving, I did have some bolts back out on mine.
Click to expand...

This is really great, thank you. Going to read this alongside the FSM before I tackle the job.

Are you happy with the manifold you chose?
 
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