Exhaust Manifold Gaskets

[isptbart]

I started up our 2007 HR 42PLQ Scepter, 400ISL w/approx. 111K miles. Two days ago, while on a trip, upon starting my coach, I heard a substantial clattering noise. Checked out everything I could think of, I then decided to drive on. 40 miles later, stopped at a rest stop & no more noise. Same order of things the next day & after crawling under the coach & seeing nothing, we moved on again. After stopping for the evening & letting everything cool down, I started up the coach again & noise had returned. Opened up the two rear access hatches in the bedroom & found the issue - at least two exhaust manifold gaskets were leaking. I checked the bolts & they are good & tight, so I didn't try to force them any tighter. Other than some carbon buildup, they seem to pretty well seal up once getting to a driving temp. Thinking about continuing on our trip for 1K to return home, to either have it serviced or do it myself? Nothing noted close by that I saw which could get damaged?

I have what appears to be a two-piece exhaust manifold. I have never tried to change out these gaskets, so looking for some guidance on the use of some type of penetrating oil/liquid, removing the bolts w/o breaking them off (use of an impact wrench?), replacing all of the six gaskets, necessary to disconnect any of the turbo, or other parts, etc.? Now might be a good time to adjust the valves too? Other ideas?

Thanks in advance for guidance!

Bart from VA

[96 EVO]

Bart, I haven't tried it myself, but I've read many, many times, the best penetrating oil is a 50/50 mix of ATF and acetone.

[Rocketman3]

At our last annual service the tech noticed the carbon indicator that 2 of the gaskets had failed.  
 

I had him order (all 6) them in and replace them- he put penetration oil on them as soon as I gave him the go signal- then more the next morning - then more just as he started the job when parts arrived (abt noon). No broken bolts! Yea!

 

Good Luck

[isptbart]

96 EVO - I had read that before but never used it. Hey thanks!

Rocketman3 - did he use an impact, wrenches or socket? Did you replace the bolts too when you replaced the gaskets?

Thanks guys!

Bart

[Rocketman3]

I remember he used the “most” popular commercial penetration spray (don’t remember now what it was).

I don’t remember what he used to break loose the bolts. 

[zmotorsports]

Personally, I'm a Kroil fan.  Aerokroil to be specific.  Started using it 35-years ago when I entered the industrial maintenance industry and have been a fan ever since.

 

When I had to remove my exhaust manifold I soaked it down a couple nights before the work was to begin and I didn't end up breaking any more fasteners than the two that were already broken.  Last year when I had to rebuild the turbo on my 2006 Duramax, I soaked the fasteners down a couple night prior and I was able to remove all 12 fasteners without a single one being broken.  On the Duramax forums all I had read about were people breaking fasteners when removing their turbos so I was either very lucky OR Kroil works.  🤔

If you will be removing to replace gaskets, I highly recommend replacing all of the fasteners with OEM Cummins fasteners.  I am not a fan of reusing the exhaust fasteners after that many heat cycles.  

 

[Ivan K]

When you tried to tighten the bolts, did they move at all? The install torque is pretty low (35lbs on mine) so if you could tighten them at all, you should be in good shape. I did not have to spray mine at all and they looked almost like new when removed. The turbo studs needed some lube . The spacers however needed a bath in rust remover to look good. I had similar cold leak on a Ford class C that stopped when warmed up, it ran fine after hot. You might loose some turbo efficiency and moisture can eat on the manifold flange where it isn't tight against the gasket if left for long time and hopefully not melting hoses or wire insulation.

[BradHend]

I hope you have success with getting the bolts out.  It’s quite a job if they don’t want to come out or you break 3/4 of them as was my case.  I also used RemFlex gaskets which so far have not given me any issues.  

[bobdinsmore]

Just a couple of weeks ago I used the 50/50 ATF/Acetone mixture when trying with absolutely success to remove a mower blade. No success after SOAKING it with PB Blaster. After just the first squirt with the 50/50 mix, it was unbelievably easy to remove. A totally scientific sample of one, but I'm very impressed and it will be my go-to in the future.

[cbr046]

Project Farms on YouTube did a test of various penetrating oils, including 50/50 acetone/ATF.  https://www.youtube.com/watch?v=xUEob2oAKVs

Another video showed the "mechanic" loosening the manifold bolt a bit, just a bit, then re-tightening, then loosen again, then tighten, working the bolt back-and-forth until it worked free.  It seemed a pretty reliable way to avoid BBDS (broken bolt disaster syndrome).

It might be worthwhile to replace the manifolds (both sets), or at least have them checked for warpage.  I'm also a big fan of OEM parts in this case (although I'd give a thumbs up for the RemFlex gaskets). 

My manifold has been leaking at the manifold gasket for some time and need of being replaced.  I'm too chicken to address the issue and too cheap to have it professionally done, not to mention the challenge of contorting my body into impossible positions.  I've had to clean the radiators twice now as they get gunked up with soot. 

Good luck with yours.

- bob

[96 EVO]

36 minutes ago, cbr046 said:

 

My manifold has been leaking at the manifold gasket for some time and need of being replaced.  I'm too chicken to address the issue and too cheap to have it professionally done 

LOL!

Your stuck between a rock and a hard place, aren't ya 

[Rikadoo]

So wheni did my manifold i soaked them down the day before, one half tri-flo the other was a new product out here “kroil” using a wratchet nieter one moved, used my 3/8 impact they All came out, the hardest part was reinstalling the bolts for the turbo drain. Worked out ok, no more exhaust noises… we cept for the flow thru muffler, the engine breaths sooooo much better

[Happycarz]

For years I used Liquid Wrench as a penetrant.  Then I found Kroil.  I ran out on a project and made a batch of 50/50 ATF & acetone. It didn’t do the job! No comparison. Now I always make sure I have a backup supply of Kroil.  

When using Kroil, I have never been let down. I don’t even think I’ll have a problem anymore. It just works.  

The worst case was loosening a rusted lock nut on a friend’s Camelot with a TRW steering gearbox. That’s the one where you hold the adjusting screw with a stubby screwdriver and turn the jam lock nut. (Tight quarters) This 2008 Camelot had never been adjusted and the coach lived in a wet and humid environment. When backing out the lock nut, the adjuster screw backed out too.  There was no way to move them independently. I soaked them for 2 days and attempted to free up the nut, being careful to not mess up the screw slot. Along the way I had been tapping the nut with a hammer trying to gain a tiny bit of free space between the threads. On the third day I got about a ½° movement. I then know I was going to win. For the next 1 ½ hours I worked back and forth, tapped it and added a bit of Kroil. IT WORKED!  I could spin the nut with my fingers when done.

Then I got back to the task at hand of adjusting the free play out of the steering box, which was very easy to finish.

I’ve read where folks have had great luck with the 50/50 mixture of ATF & acetone. It just didn’t work for me when working on a job that was easier than the one above.  I vote for Kroil.

[96 EVO]

11 minutes ago, Happycarz said:

   There was no way to move them independently. I soaked them for 2 days and attempted to free up the nut, being careful to not mess up the screw slot. 

Would have been nice of them to have used an Allen or Torx head screw in that position!

[Happycarz]

Too many bean counters involved!

[Ken Smith]

It been my experience that if you have a gasket leak on a 400 ISL and only want to fix it once. Do the following:

1. Be careful removing the studs and bolts so they don't break. (PB Blaster or Kroil and lots of patiences)

2. Replace all studs and bolts with OEM Cummins.

3. Resurface or Replace both manifolds. Most gasket blow-outs are from warped manifolds.

4. Reassemble using gray anti-seize on all studs & bolts.

5. Torque all bolts and studs to Cummins specs. (Very important to use recomended pattern sequence when tightning)

[dl_racing427]

PB Blaster and an impact wrench with the pressure turned down eventually got the bolts out of my C-Series manifold.
I ended up replacing the head, as the leak was a cracked exhaust port.
I bought appropriate length stainless bolts to use when reassembling, fully coating them with anti-seize and torquing to spec.  No problems since.

[96 EVO]

Sounds like it's not a matter of 'IF' you will have issues with the exhaust manifold on these Cummins engines...... It's a matter of 'WHEN' ☹️!

[Guest Ray Davis]

4 hours ago, dl_racing427 said:

PB Blaster and an impact wrench with the pressure turned down eventually got the bolts out of my C-Series manifold.
I ended up replacing the head, as the leak was a cracked exhaust port.
I bought appropriate length stainless bolts to use when reassembling, fully coating them with anti-seize and torquing to spec.  No problems since.

David is correct, gentle hammering with an impact tool has usually worked the best for me.   Brad came up with a nifty tool that will turn a bolt, nut, or stud red not in a jiffy using elect induction, it's an amazing little device.

Just about any bolt I have ever broken was with a breaker bar & socket,  not knowing when to quit & using just a wee bit more force.   

[BradHend]

Again, I wish you the utmost luck and success with this undertaking.  
As others have mentioned, a warped manifold could make this an extremely annoying and costly project.
If you suspect a slightly warped manifold, I might suggest at least trying RemFlex gaskets.  They are 1/8” thick and designed to rebound when compressed.  OEM gaskets will not fix anything if your manifold is indeed warped.  
I hope to heck the larger piece of your two-piece manifold isn’t Cummins Part #3955199. 
Also as @Ray Davis mentioned, I do credit that induction heater with getting me at least 3 bolts out without breaking anything.   I lubed the heck out of em, heated the mounting spacer piece up cherry red hot with that tool, and gently back and forthed it out.  Spray lubing after each heat cycle.  Did a few cycles.  Lots and lots of white smoke, but  the idea is that the penetrate wicks in better that way.  
I’m sure your coach is in much better shape than mine is so hopefully you’ll be just fine and it won’t be that big of deal.  But you should still be prepared.  I ended replacing the turbo, all the line sets, the EGR valve, radiator lines…basically everything on that side of the engine.  It sucked.  I wasn’t prepared for that much work.  Had to learn, research, order and buy a lot of tooling, and I had to do it all in my driveway.  Good times. 
Keep us updated!
 

IMG_0707.heic IMG_0708.heic 70940252102__B67BB7A8-7E58-4B88-A9CB-C8437B202BE4.heic

Edited November 18, 2023 by BradHend

[isptbart]

Thanks to you all!

Brad - can you send/post me info about the induction device to heat up the bolts?

Thanks! Bart from VA

[BradHend]

The one I used was purchased on Amazon and made by a company called Solary and was the 1000 watt model.  
There is most likely better quality options out there, but this one worked for me and has come in handy for various other issues.  
I’m not saying you need to purchase this quite yet, more of a suggestion/solution if push comes to shove. 

 

Edited November 18, 2023 by BradHend

[Alan Goolsby]

Changed the gasket on my 95 Dynasty several years back. I used the same procedure as Ken Smith and others have suggested. I can say that the most stressful and hardest part was removing the bolts. Patience and Kroil is your friend. I soaked the bolts and just rattled them with the impact wrench a couple of times a day for a week. Then I started trying to loosen them, all came loose but the usual last one. I broke it off. There is that fine line when you are trying to wiggle them back and forth to loosen them. You can’t tell if it’s really loosening or the bolt is stretching. I researched removing a broken bolt. Don’t try to drill it out yourself, unless you’re as talented as Van Williams or Zsports. I hired a welder to come out and weld a nut on the remaining part of the bolt. Guess the heat helped because it then came right out. What a relief. The rest was easy.

Alan Goolsby

95 Dynasty 

 

[zmotorsports]

This is the inductance heater that I have, although a much older version.  It works well in some applications but many times accessibility render it useless.  

https://www.theinductor.com/induction-heater-tools-store/mini-ductor/mini-ductor-ii

 

As for exhaust manifold warpage, in my exhaust manifold and turbo replacement video in the library I show how to measure for sealing surface flatness and what I've found to be the limits for what gaskets can get away with.  I won't lie anything on an engine with not than .004" clearance as I've found you'll be doing it again in sorry order.

 

I used to set them up on the milling machine and flycut them flat but for the past 15 or so years now I just use my belt sander with 120-grit belt.  Works faster and gets it dead nuts flat as I show in my video.  I've even seen brand new manifolds (green)  over my .004" limit.  

[Jeff H]

I had a leak on my 400 ISL, but it got worse as the engine got hot.  There was about 1/2" of one gasket missing and damage to another.  The manifold was warped.  Being on the road and not having tools or time to deal with broken bolts I went to Cummins in El Paso.  Not cheap but they were very good, got me in right away, had a place with power for us to park over night.  I soaked the manifold bolts with PB Blaster a couple times a day for a couple days before we brought it in.  All the manifold bolts came out.  2 of the bolts in the turbo that I didn't soak (duh) did break so it seems like the oil helps. 

Apparently warped exhaust manifolds are quite common on the ISL

Edited November 19, 2023 by Jeff H
added info