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Exhaust Manifold Leak


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I have an exhaust manifold leak on my 2003 Signature with a Cummins ISX 525 hp engine. I was going to have Cummins in Orlando do the repairs but after them having my coach for a month and still no defined window or schedule of when it would be done, ('we will get to it when a Tech is available but do not know when as we have less than half of the techs we need') and after contacting Cummins in Tampa and 2 other repair shops with zero response I have decided to do the repair myself. Before I get started on it I would appreciated any pointers from anyone who has done the same so I can avoid any unnecessary mistakes. I have the time and expertise but do not do this for a living so would appreciate any help and advice. 

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First thing I'd do is get on the Quickserve site and get the part numbers of the manifold, studs, and gaskets to make sure they are available.  When I bought my manifold and parts for my 8.3 ISC  back in 2015 the cost was ~$600 but from what I'm seeing the price doubled and and if you have a shop do it plan on even more at $160/hour.  It took me about 8 hours to do mine but I wasn't in a hurry. 

Prior to starting clean out the closet and prepare the work area.  No matter what you will get dirty and anything you touch will get dirty.  I worked through both my engine hatches.  Good lighting is a must.  If not working over concrete lay down some plastic, it will make finding dropped parts/tools easier. 

Spray down the studs/bolts a couple days ahead of time, I used BBlaster which worked good, didn't have a problem getting the studs out.

When I changed mine I tried to leave the Turbo in place, which was a mistake, I ended up completely taking it out. 

The R&R was pretty straight forward, not rocket science.  If you have a helper it might help, when I was putting mine back every time I dropped a tool or part I'd have to get up and go get it. 

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My Sig has the side mounted radiator and I am planning on taking it out so I can have good access to the Manifold. I have some (2) broken bolts to get at so need to make sure I have the room to get at them to drill them out if necessary, thoughts, suggestions? I would have to dismantle a good portion of my closet to get at the bulk of the manifold. 

I have all the parts I need. 

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If you think taking the radiator out is the lessor of two evils then go for it.   I had pretty good access to mine through the closets and bedroom hatch, never even considered taking out the radiator.  R&R of the radiator stack is a pretty big job and adds another layer of complexity to the job.  It would be my last choice. 

I didn't have any broken bolts (knock on wood).  I think I would of had room to get a drill in there to drill them out if I did.  Would have been a pain but doable. 

Maybe that's why the shops not in too much of a hurry to tackle the job, having to take the radiator out would have added to cost significantly.  If I had the radiator and CAC out I'd take and have them cleaned/checked.  Don't be surprised if the CAC is leaking, mine cost ~$1650 to have it checked and repaired, I didn't think it was leaking.

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I realize that our engines are different, ISX 525 versus ISC 350, along with the size of the engine compartments, however the engine repair techs that replaced my exhaust manifold did the entire job from the outside. They never went inside the coach.

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20 minutes ago, Dr4Film said:

I realize that our engines are different, ISX 525 versus ISC 350, along with the size of the engine compartments, however the engine repair techs that replaced my exhaust manifold did the entire job from the outside. They never went inside the coach.

Did they remove the radiator or cooling fan. 

I'm not a small person, no way could I squeeze up there and work on my exhaust.  But I also know that a good mechanic will find a way, in the mines I worked at we use to work on equipment in the field and the mechanics would get pretty creative to get things done.  The foremen knew which guys could get things done and did use size/agility as a determining factor when assigning jobs. 

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7 minutes ago, jacwjames said:

Did they remove the radiator or cooling fan?

Nope, they did everything from the rear through the engine cover. They most likely removed the large air filter and hoses running across the top of the engine giving them more work to work. 

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I have all the parts I need. I will check again in the morning the closet area. Which is the easiest to gain access? Dismantle part of the closet or remove the radiator etc. It is really tight through the access cover inside the coach and very awkward to get. Removing the radiator is not the end of the world but does add complexity to the job but will enable a good clean and a good check of the cooling fan motors, cooling fluid lines and hydraulic lines etc.

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I used the access hatch in the closet to work on the exhaust manifold.  It allowed me to reach all the way to the front of the engine (pulley end).   Not to bad but you pretty much have to lay down and work upside down.   I have broad shoulders but was able to do it. 

 

I had to have my radiator replaced back in 2015, it was damaged by road debris and my insurance did cover it.  I visited the shop multiple times while they were tearing it apart.  They had the luxury of having a lift to raise the coach up, looked like a pretty daunting task.  I believe they took it out as an assembly with the fan attached, then broke it down. 

You will have to have the coach elevated a little to be able to get the the radiator out.  I have read where people have left the CAC in place and dropped the radiator down. 

Maybe someone can comment on any issues/tricks to remove the radiator and or CAC.  Even with the radiator out you would have to content with the structure of the chassis frame and trailing arms. 

Good luck and keep us updated, these types of posts are always interesting to me, learn something new every day. 

Jim J

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Jim, what rig do you have? My engine access cover is forward of the closet and I would need to be really skinny and a contortionist to get at the front (towards the back of the motor home) portion of the manifold and Turbo from that. I will check out removing some of the closet floor to get at it. As I said earlier I have lots of time. Really appreciate the feed back!!!!

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50 minutes ago, Rob M cKeown said:

Jim, what rig do you have? My engine access cover is forward of the closet and I would need to be really skinny and a contortionist to get at the front (towards the back of the motor home) portion of the manifold and Turbo from that. I will check out removing some of the closet floor to get at it. As I said earlier I have lots of time. Really appreciate the feed back!!!!

I've got a 2002 Windsor, same as Richards,

I have two hatch covers, one in front of my closet, and a second one in the closet.  Both run length wise across coach.  The one in the closet is bigger then the other hatch.  Still have to do some reaching but not bad. 

 

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Good advice from JMO, will do. I am going to check my closet floor tomorrow for the second hatch cover. If I have one it is not obvious as I have had the coach since 2006 and never noticed another one. Mind you, I haven't had a reason to look really close up until now. Anything I have needed to check has been from the front hatch. 

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Hope II"m not faced with this task anytime soon. Wonder if it would be advisable to replace all studs given the difficult access and hot/cold cycle they are subjected to.

 

 

 

 

 

 

 

 

Edited by Gary Cole
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6 hours ago, Gary Cole said:

Hope II"m not faced with this task anytime soon. Wonder if it would be advisable to replace all studs given the difficult access and hot/cold cycle they are subjected to.

 

 

 

 

 

 

Absolutely, without a question!

 Along with the turbo mounting bolts and any gaskets and o rings!

 This might be of some help too!

 

Edited by Jdw12345
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In my case my manifold cracked, which is a common problem with the ISC engines.  The failure was usually in the same location similar to what is shown in the previous video.  Many reports of this on the IRV2 forum.   Last year finding a replacement manifold became difficult especially if you wanted OEM Cummins part and in some cases aftermarket.  There was a design change in the manifold telling me that Cummins recognized there was a problem. 

So changing the studs might help in regards to that aspect but doubt it will make a difference on the exhaust manifold failure.

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Thanks for all the responses, much appreciated. I have all new bolts, seals and gaskets. I will be posting progress as I get at it. It was kind of funny in a way, I didn't even know I had a leak. I had an unrelated problem with my transmission and took it to Detroit Allison in Tampa to get it diagnosed. The Service Manager told me when he was walking up to the coach to diagnose the problem I had an Exhaust leak. I'm pretty sure it has been leaking for quite a while as the engine did not sound any different to me and I have had it since 2006. I looked at the video, the ISX 15 is definitely a different beast than the ISC.

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Fwiw, the video is an ISL, and yes, it’s a different engine but I posted it to answer your question about general removal and working through the access panels in your coach VES removal of the cooling stack. The video was for general knowledge.

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My exhaust manifold failured right after I had a catastrophic radiator failure, road debris.   When it failed I was in climbing up and down ridges in E TN, no doubt the engine and exhaust was hot.  I had to have the coach towed to have the radiator stack repaired.  Drove it home and as the first time I started the coach cold I heard the high pitch whistle of the exhaust, very distinct sound that I had not heard before.  Lifted the bedroom hatch and saw the problem immediately. 

Is your exhaust leak due to the bolts being broken or is it cracked/warped.   Either way it needs to be fixed. 

 

Edited by jacwjames
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Unless you have a safe way to raise the coach getting the radiator out is tough.  It is too tall to drop out....so either jacked about 10in or ramps, and the fan assembly is heavy too.  Think come along...all in tight quarters.  Have done manifold without removing radiator too. Depends a LOT on floor plan/access.

IF...you have to drill a broken stud make a template/drill guide that attaches on adjacent bolts...that head is soft and an off center drilling will get you a pulled head.

Slow and easy...now you know why Cummins is blowing you off.  

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 I had a good look this morning, I had forgotten I had covered up the other inspection hatch with a rubber flooring in the closet. I had to remove the 2 closet door mirrors, the bottom rail the mirrors slide on and the carpeted facia board to get the hatch out. I can get at 10 of the bolts and the Turbo assembly without too much difficulty but the front 2 are a different story. Difficult but doable. The Manifold is a 3 piece set up. Scrap removing the Radiator, would only make the job marginally easier.

 

 

 

 

 

 

 

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Well that opened it up quite a bit and looks like you have fairly decent access, might be better then mine although the hatch in the closet was closer to the front of the engine. 

Looking at the manifold pictures I didn't see any place that looked like a crack, have you identified where the exhaust leak is?

First opportunity I'd spray down the bolts and let it soak in for a while. 

Good luck

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