ISM Exhaust Manifold

[Indydyne]

My number 6 cylinder exhaust manifold is leaking at the head. I have a 3 piece exhaust manifold. Is it possible to remove the number 6 manifold and leave the rest installed?

[BradHend]

Looked at your manifold specs, I’d say no.  
If you’re able to get the bolts out of 5 & 6, it’s quite possible to remove that piece without too much trouble if things are in okay condition.  Biggest challenge might actually be getting the manifold off the other section without damaging anything and without loosening the other bolts, then at that point you might as well replace all the gaskets. 

Looking more it appears there are manifolds on the ISM with a single manifold for 1&6 that connect to a four port manifold for 2345.  Is that what your setup is?

I now shutter at the thought of exhaust manifolds and consequential damage on my rig.  Done that tap dance the hard way, hope to never have to do it again. 😂

Edited May 4, 2024 by BradHend
Looked deeper.

[Ivan K]

10 minutes ago, Indydyne said:

My number 6 cylinder exhaust manifold is leaking at the head. I have a 3 piece exhaust manifold. Is it possible to remove the number 6 manifold and leave the rest installed?

Interesting idea but I doubt it could be wiggled out without loosening all the manifold bolts. Once you have enough space to rotate it a bit, it should come out. It is a machined fit, will depend on the rust but mine was pretty clean in that area.

But then again, once you get the bolts loose and slide the manifold away far enough to just replace the gasket, that would be the way to do it. It is an approved method and #6 is the easiest to clean the old gasket remnants. Don't drop them in the holes.

Edited May 4, 2024 by Ivan K

[Indydyne]

BradHend,

I do in fact have a single horn for 1, a four port section for 2345, and another single horn for 6.  I am hopeful that I can loosen the two bolts for 6 and start the wiggle dance to remove.  All other ports are thankfully not leaking. 

[BradHend]

Well in that case, if you can indeed get those bolts out, I’d try it.  It will be tight though. Taper fit and really no way of getting much wiggle.  
when I was trying to separate my two piece, I fashioned up a slide hammer of sorts which eventually did work.  Huge PITA mind you.  Not a lot of room in there.  

Edited May 4, 2024 by BradHend

[Jdw12345]

A couple of things to consider, imo, how long are you planing on keep the coach, and if that answer is a number of years, then I would say you should probably remove the entire exhaust manifold and replace all of the exhaust manifold gaskets…… and be done with it.

 Coming from running our own trucking business it’s more cost effective to fix these types of issues once and not have to deal with it again. I haven’t heard about a significant amount of ISM’s with manifold issues like the ISL’s but I’m not an ISM owner so I don’t look for problems with that power plant. Chances are that there’s another gasket issue right around the corner but then again maybe not, you never know, at 24 years old it’s a crap shoot! JMO!

[Patrick Roman]

Always the biggest fear when removing exhaust manifold studs is snapping them off in the head once that happens you have a real problem getting them out. The old way was using a torch now they have a new invention called an induction stud removal kit that is a game changer works like magic. Check it out could save you a huge headache 

[Ivan K]

When I found a leak, I tried to torque the bolts to prescribed 35lbs and they easily turned a quarter of the turn. Of course that did not help so out they went without any problems. Trying to soak the threads was futile, pretty much non of the penetrant made it past the spacers unless the bolts were already backed off a little. And if the manifold needs to be backed out to replace one gasket, pretty good chance that the others get torn up doing it. It helps big time to temporarily replace a couple of bolts with studs so the manifold slides out and into its place easily. Not a bad job, just heavy with the turbo and deep in the hole, nothing like access on a truck.

[Paul J A]

Try a penetrating agent of 50%  ATF and 50% acetone. Best one I have ever used with excellent results. 

[dl_racing427]

I also think I'd replace all the gaskets while I was at it.  Do it once and be done with it.
There are threads on here that detail several methods for removing manifold bolts without breaking them.
A search will give you some very valuable advice.
Believe me, taking your time to remove those bolts properly is infinitely preferable to the headache of dealing with a broken bolt.

Good luck.

[Paul J A]

Ivan; "It helps big time to temporarily replace a couple of bolts with studs so the manifold slides out and into its place easily." 

Put a coat of a penetrating agent on those threads will help too. Might be able to use air and blow residue out before inserting the bolts used for the manifold installation.

Edited May 5, 2024 by Paul J A
clarify

[Ivan K]

11 minutes ago, Paul J A said:

Ivan; "It helps big time to temporarily replace a couple of bolts with studs so the manifold slides out and into its place easily." 

Put a coat of a penetrating agent on those threads will help too. Might be able to use air and blow residue out before inserting the bolts used for the manifold installation.

Yes, blowing out the blind holes is always good idea, I did not have to chase the threads since there wasn't any rust and bolts came out nicely but I used a bit of high temp antiseize in case I have to ever do it again. The couple of longer studs (cut of heads of long 10mm bolts) made positioning the gaskets and manifold easy.

[Paul J A]

Yep. And you can cut a slot in the end of the Studs for a screw driver to inset , remove too.

Turn down Allen head bolt heads to make studs too. IF you have the room.