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Unread 07-01-2009, 11:56 PM   #1
CMARJEEP
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Has anyone replaced a WJ exhaust manifold? How difficult?

After wheeling the other day I now have an exhaust leak coming from the manifold area. I can't really narrow it down but it sounds like its coming from the rear exhaust manifold. I think its a small leak because it quiets down/stops when the engine gets heated up. I hit the exhaust pretty hard though on some rocks so I hope I didn't crack it. I can also faintly smell an exhaust odor when the engine first starts up in the engine bay.

Does anyone have any advice on how to go about narrowing down where the leak is? My buddy told me to wait about a week or so and see if I can see any black buildup in any areas. Its just really hard to get a good view of the manifold area with all the crap around it.

Now for the people that have replaced them, how difficult of a job is it? Is it something I can do in a day or more of a weekend project? Looking at the FSM it doesn't look too complicated although some bolts look hard to get at. Also it looks like I have to disconnect the fuel rail and some other intake items.

Pretty much I'm just looking for some helpful hints on how to go about this to make it as simple as possible. THANKS A LOT!

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Unread 07-01-2009, 11:59 PM   #2
xJoshxx
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To find where it's at run some Amsoil power foam or Seafoam and sit under it any spots and it will puff out white smoke thats how i found my Leak. and welded the hole back up.

No idea on how But i believe the bolts Are touchy. Soak FOR MANY MANY days with Pb blaster Pb blaster likes hot surfaces 2 so it works better when hot.

ive heard of many snapped and cracked Manifold bolts. on the 4.0Slows

which is why ive been putting off changing my Headgasket.
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Unread 07-02-2009, 12:04 AM   #3
CMARJEEP
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Quote:
Originally Posted by xJoshxx View Post
To find where it's at run some Amsoil power foam or Seafoam and sit under it any spots and it will puff out white smoke thats how i found my Leak. and welded the hole back up.

No idea on how But i believe the bolts Are touchy. Soak FOR MANY MANY days with Pb blaster Pb blaster likes hot surfaces 2 so it works better when hot.

ive heard of many snapped and cracked Manifold bolts. on the 4.0Slows

which is why ive been putting off changing my Headgasket.
Thats a good idea. I have some Seafoam laying around so I will do that tomorrow.

That would really suck if a bolt snapped. I'm sure that would just be a joy to fix. Hopefully its somewhere where I can just repair it without taking anything/too much apart.

Thanks for the advice.
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Unread 07-02-2009, 12:07 AM   #4
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http://www.youtube.com/watch?v=GSGR3...er_profilepage

watch it carefully ull see my leak
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Originally Posted by moPowered View Post
The SRt-8's are a liberty design.
2011 WK2 ORA2
2012 WK2 SRT8
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Unread 07-02-2009, 12:41 AM   #5
MEinSoCal
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i've done it twice and i still thinks its a ***** and the biggest PITA. its helps if you have small hands and skinny arms to squeeze under the exhaust manifold to feel and find all the hidden bolts underneath. also should you decide to upgrade to a header, it may make things a little more difficult as the runner tubes are bigger. also i remember the first time, the bolts connecting to my downpipe were rusted to i ended up having to cut those off too. if things went smoothly, technically this should only about a 1-2hr job. for me though, it always turns into an all day nightmare.

as for the fuel rail, no need to disconnect. just move the rail out of the way.
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Unread 07-02-2009, 12:47 AM   #6
CMARJEEP
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I'm looking to just keep everything stock. I am going to do what Josh said with the Seafoam tomorrow and see if I can narrow down where the leak is coming from. I'm hoping its just the gasket or something that got messed up when I hit the exhaust on a rock.

Just curious, how much would a shop charge to do this?
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Unread 07-02-2009, 12:53 AM   #7
MEinSoCal
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i'd imagine a shop would charge about 1.5hrs of labor. if you do decide to try it, be prepared with lots of different length socket extensions, and maybe even a wobble extension.
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Unread 07-02-2009, 01:22 AM   #8
CMARJEEP
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I will call my mechanic tomorrow and see what he wants to charge for it. If its only a couple hundred I might just have him do it. Save me a headache. But I'm not even sure yet where the leak exactly is.
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Unread 07-02-2009, 03:01 AM   #9
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Well, I've got the 4.7 so I can't exactly relate but I had the exact symptoms and it was a broken bolt, actually I realized it was two when I got it all apart. I was so worried about them being seized and hard to remove once the manifold was off. If it is a broken bolt get a can of Liquid Wrench and spray them really good for a few days. After doing that, mine came out with a pair of vise grips pretty easy. The job sounds alot harder than it really is and I think I have less working room on my 4.7, some of those bolts were a PITA to get to but I pulled it off in one night after work till 1:00am. Just keep swimming, just keep swimming!!! I have the program ALL DATA if you need any specifics, torque specs, or a full sheet of instructions and diagrams if needed. Shoot your e-mail address if you need any of that stuff.
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Unread 07-02-2009, 03:18 AM   #10
CMARJEEP
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Quote:
Originally Posted by UrbanOffRoad124 View Post
Well, I've got the 4.7 so I can't exactly relate but I had the exact symptoms and it was a broken bolt, actually I realized it was two when I got it all apart. I was so worried about them being seized and hard to remove once the manifold was off. If it is a broken bolt get a can of Liquid Wrench and spray them really good for a few days. After doing that, mine came out with a pair of vise grips pretty easy. The job sounds alot harder than it really is and I think I have less working room on my 4.7, some of those bolts were a PITA to get to but I pulled it off in one night after work till 1:00am. Just keep swimming, just keep swimming!!! I have the program ALL DATA if you need any specifics, torque specs, or a full sheet of instructions and diagrams if needed. Shoot your e-mail address if you need any of that stuff.
Thanks for the advice. I've been reading all the past threads on JF about replacing it and people have been saying its not a difficult job, just time consuming. Thanks for the offer on All Data but I have a FSM with all the diagrams and everything.
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Unread 07-02-2009, 10:37 PM   #11
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ive done it on the 4.0 three times. take my advice, if you remove it dont have it welded up because it will just crack again a few months later. if you replace it go with a manifold that has the expansion joints, those will keep it from cracking. also be careful with the first and last studs.

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Unread 07-02-2009, 10:56 PM   #12
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Quote:
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ive done it on the 4.0 three times. take my advice, if you remove it dont have it welded up because it will just crack again a few months later. if you replace it go with a manifold that has the expansion joints, those will keep it from cracking. also be careful with the first and last studs.

like the DT/ML Headers for the WJ Ceramic coated and expansion joints
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Unread 07-02-2009, 11:07 PM   #13
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Here's a tip for finding the leak:
With the truck cold, and jacked up enough to slide under, have a friend start it up, then plug the tailpipe by holding a wadded-up rag over the end. The bottom of his shoe will hold it if he's sitting on the floor, and he won't get burned!
Then you can listen for leaks, and put your hand near where you suspect the leak; you'll feel the exhaust puffing against your hand when you find the leak, and since the engine's still cold, it won't be hot enough to burn you.
- R
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Unread 07-02-2009, 11:08 PM   #14
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While you have it off, why don't you port and polish it.
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Unread 07-02-2009, 11:25 PM   #15
Kruzin
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4.0s exhaust manifolds crack and leak.
Always have. Always will.
Replace it with a factory manifold.
It'll crack and leak.
Replace it with a cheap aftermarket manifold.
I'tll crack and leak.
Replace it with an expensive header.
It'll crack and leak.

Some get lucky and go a few years without it crackin.
Any way you slice it, it WILL eventually crack and leak sooner or later.
It's a fact of life with the 4.0s.

Just buy the cheapest you can find, and expect to replace it in 2 years.
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