Exhaust manifold replacement advice
Thread Starter
CF Veteran
Joined: Nov 2017
Posts: 3,700
Likes: 238
From: Groton, MA
Year: 1995
Model: Cherokee(XJ)
Engine: I6 4.0L
One tip I"ll pass on for when you put everything back together. You will need to remove the intake as well. When you put it back together, put the bolts/washers in the hole prior to putting the intake manifold back on. I tried for a long time to to get them in after the intake was in place and got really frustrated. I finally figured out you can put them in and then set the intake manifold on top of them and then start tightening them.
Another tip is to make 100% sure you get the intake onto the cylinder head dowels. If the engine revs up when you start, you most likely missed the intake positioning on the dowels. It can feel like it is in the right place, but actually sitting on top of the dowels.
I have replaced the exhaust manifold on both of my XJs (98 and 99) and was able to reuse the hardware with no issues. I have had the fuel line disconnect off several times on both XJs and have never replaced the orings. I highly recommend getting a fuel line disconnect tool for when you remove it. That will save you a ton of time. I bought the metal set from harbor freight and it has worked great.
Another tip is to make 100% sure you get the intake onto the cylinder head dowels. If the engine revs up when you start, you most likely missed the intake positioning on the dowels. It can feel like it is in the right place, but actually sitting on top of the dowels.
I have replaced the exhaust manifold on both of my XJs (98 and 99) and was able to reuse the hardware with no issues. I have had the fuel line disconnect off several times on both XJs and have never replaced the orings. I highly recommend getting a fuel line disconnect tool for when you remove it. That will save you a ton of time. I bought the metal set from harbor freight and it has worked great.
Thread Starter
CF Veteran
Joined: Nov 2017
Posts: 3,700
Likes: 238
From: Groton, MA
Year: 1995
Model: Cherokee(XJ)
Engine: I6 4.0L
Absolutely. I just had it off when doing my coolant flush - I can't imagine trying to get at the manifolds with it in the way. 
As much as I'd love to properly torque everything to exact spec - I feel like what will happen in reality is that I'll hit the most accessible ones with the torque wrench to get a feel for the proper torque, and then on the awkward ones, I'll tighten to the best guess.
17ft/lbs and 23ft/lbs is a lot lower than I would have guessed. I'll have to break out the small torque wrench to go under 20.
What is the risk of going slightly over on these bolts? I can't imagine the fasteners will snap off in the 20 ft/lb range, would they?
17ft/lbs and 23ft/lbs is a lot lower than I would have guessed. I'll have to break out the small torque wrench to go under 20.
What is the risk of going slightly over on these bolts? I can't imagine the fasteners will snap off in the 20 ft/lb range, would they?
Senior Member
Joined: May 2015
Posts: 736
Likes: 5
From: Louisville KY
Year: 01
Model: Cherokee
I torqued all my bolts to 29 ft/lbs in the proper order, then went back around and tightened a couple more ugga duggas in the correct pattern. Works well. The idea being that you still follow the pattern even if you’re not torquing to spec
Senior Member
Joined: Mar 2010
Posts: 589
Likes: 0
From: Alaska
Model: Cherokee(XJ)
interesting tread with good information and lots of tips
the extentions setting off torque specifinations
conical washers
fuel rail aside with line still connected
dowel line up
and a lot more..
marc
lots of things i didnt think of yet while in near future doing my 88 xj manifold
edit: how did you go through this or are you still in the middle of doing it ? any other tips you might run into ?
when you go this deep do you replace your freeze plugs too ?
the extentions setting off torque specifinations
conical washers
fuel rail aside with line still connected
dowel line up
and a lot more..
marc
lots of things i didnt think of yet while in near future doing my 88 xj manifold
edit: how did you go through this or are you still in the middle of doing it ? any other tips you might run into ?
when you go this deep do you replace your freeze plugs too ?
Last edited by LadyKenai; Apr 16, 2018 at 05:57 PM.
Thread Starter
CF Veteran
Joined: Nov 2017
Posts: 3,700
Likes: 238
From: Groton, MA
Year: 1995
Model: Cherokee(XJ)
Engine: I6 4.0L
I haven't started this. I'm hoping to do it this Sat, but that will depend on whether my parents are around to watch the kids.
I will report back after completion with how it went.
There's another thread on flange thickness with the aftermarket manifolds and there being potential problems. The OP on that thread used washers to level the flanges, so I'm anticipating having to do something similar.
I will report back after completion with how it went.
There's another thread on flange thickness with the aftermarket manifolds and there being potential problems. The OP on that thread used washers to level the flanges, so I'm anticipating having to do something similar.
CF Veteran
Joined: Feb 2011
Posts: 1,944
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From: Henderson, NV
Year: 1999
Engine: 4.0L
Ok I’m going to suggest a few things. Don’t remove the injectors or the fuel rail. Just disconnect the fuel line. It’ll be out of the way and you can remove the intake as one assembly.
Don’t overthink it. It’s really not that hard of a job. Should take about 3 hours as long as you don’t break any bolts/studs. I keep an extra set on hand. Some headers allow you to get an extension on all of the bolts so it’s easy to remove and install. Some do not.
If you do end up with the header contacting the intake manifold grind away some of the manifold and start bashing the exhaust runner to get it all to fit.
Don’t overthink it. It’s really not that hard of a job. Should take about 3 hours as long as you don’t break any bolts/studs. I keep an extra set on hand. Some headers allow you to get an extension on all of the bolts so it’s easy to remove and install. Some do not.
If you do end up with the header contacting the intake manifold grind away some of the manifold and start bashing the exhaust runner to get it all to fit.
Senior Member
Joined: Jul 2012
Posts: 794
Likes: 104
From: Aldie, VA
Year: 1999
Model: Cherokee
Engine: 4.0
What I finally did was to test fit just the intake and see where it lines up to the top of the cylinder head. And you can try to wiggle it around to make sure it's on the dowels. I tested everything 3 times before I figured out it wasn't on the dowels. Once you know where it needs to line up with respect to the head then you can put the exhaust in place, put those middle lower manifold bolts in and thens et the intake on top of those. Easy from there.
Thread Starter
CF Veteran
Joined: Nov 2017
Posts: 3,700
Likes: 238
From: Groton, MA
Year: 1995
Model: Cherokee(XJ)
Engine: I6 4.0L
Ok I’m going to suggest a few things. Don’t remove the injectors or the fuel rail. Just disconnect the fuel line. It’ll be out of the way and you can remove the intake as one assembly.
Don’t overthink it. It’s really not that hard of a job. Should take about 3 hours as long as you don’t break any bolts/studs. I keep an extra set on hand. Some headers allow you to get an extension on all of the bolts so it’s easy to remove and install. Some do not.
If you do end up with the header contacting the intake manifold grind away some of the manifold and start bashing the exhaust runner to get it all to fit.
Don’t overthink it. It’s really not that hard of a job. Should take about 3 hours as long as you don’t break any bolts/studs. I keep an extra set on hand. Some headers allow you to get an extension on all of the bolts so it’s easy to remove and install. Some do not.
If you do end up with the header contacting the intake manifold grind away some of the manifold and start bashing the exhaust runner to get it all to fit.
I've just never done this before, so I want to gather as much advice as I can so it will go smoothly.
I'm hoping that I don't have to go so far as cutting and grinding on the manifolds, but if it comes to that - so be it.
Thread Starter
CF Veteran
Joined: Nov 2017
Posts: 3,700
Likes: 238
From: Groton, MA
Year: 1995
Model: Cherokee(XJ)
Engine: I6 4.0L
What I finally did was to test fit just the intake and see where it lines up to the top of the cylinder head. And you can try to wiggle it around to make sure it's on the dowels. I tested everything 3 times before I figured out it wasn't on the dowels. Once you know where it needs to line up with respect to the head then you can put the exhaust in place, put those middle lower manifold bolts in and thens et the intake on top of those. Easy from there.
Thread Starter
CF Veteran
Joined: Nov 2017
Posts: 3,700
Likes: 238
From: Groton, MA
Year: 1995
Model: Cherokee(XJ)
Engine: I6 4.0L
I came up with another question: The write-up I'm using mentions using high-temp thread sealant on the manifold bolts. There is no reference to this in the FSM.
What is the recommendation - use thread sealer or not?
What is the recommendation - use thread sealer or not?
