Exhaust Manifold Gaskets

[isptbart]

Hello to all responses! We are still on the road & I have been reading all of the responses - many thanks to you all! I will not be in a position to do much until I return home. In the mean time I also follow Project Farm who does all types of product testing w/o any product sponsorships. He has done several penetration fluid tests & came up with interesting results. I will begin use of penetration fluids once I get home because I feel all of it would burn off in my travels back home? Once home & will proceed wit trying to remove the exhaust bolts once I have new bolts & the RamFlex gaskets. I will report back as to my results!

Many Thanks to you all!

Bart from VA

PS - I tow my GMC 2500HD truck. Yesterday, my diesel truck went into a limp mode w/o warning & for the very 1st time ever. Changed out my fuel filter & now all is well!!! Just decided to do that before I pulled any codes because of all of the limp mode issues I have been reading about for our RV & sure work for my truck!

[BradHend]

@isptbart I should probably mention this as I don’t want to cause you more troubles...  If you decide to use the RemFlex gaskets, you will need to do them all.  They are much too thick to replace one or two of the OEM ones.  
Might also suggest getting the set for your engine versus buying a sheet and cutting them out yourself to save money.  I tried that, they do not cut worth a d***, so I ended up buying the proper stamped set from their website and basically paying twice.  😡

It’s quite a tough call to make on chancing replacing the two leaking gaskets with OEM, hoping the manifold isn’t warped and the bolts will come out fine or get yourself into the situation I got myself into. 

This is how warped my manifold was…😭

 

Edited November 20, 2023 by BradHend

[isptbart]

Brad - all good points! 

Thanks for the info update.

Bart from VA

[isptbart]

Exhaust Manifold Gaskets - Update!

All - with the cold/wet weather here in VA & my concern I might break exhaust manifold bolt(s), I decided to have a local shop take on the task. Local rates were from $125/hr to $230/hr. Estimates started at approx. $850 plus parts to a Cummins worse case scenario estimate replacing the manifold as well at $7,500! I took a $159/hr labor rate at a shop I have frequently used in the past & they worked me right in. In preparation for the bolt removal task, I heated up the engine, shut it down & sprayed with PB Blaster 6 times before taking it to the shop. The tech successfully removed all 12 bolts w/o braking, but stated he couldn't see any penetrate weepage on the threads? So, using penetration may not have been necessary in my case? Note: the stated bolt torque is only at 40#. I did have a slight manifold warp at port #3 at about .030". Ports 3 & 4 had the gasket leaks & all others were OK. Other than a new set of OEM manifolds at approx. $800, we could not find replacement manifolds with a quick delivery. I decided to follow a posted recommendation of using the Remflex compression gaskets good to about .065". They are supposed to be compressed at about 50% & torqued at only 20-24#'s. Keeping my fingers crossed the Remflex gaskets will hold up long term, in lieu of replacing the exhaust manifold. I couldn't find S/S studs as an alternate & had to wait overnight for OEM exhaust bolts, so I also authorized adjusting the valves at 114,000 miles to utilize the available down time. About 4 hours for the valve adjustment & a $75 valve gasket. The tech said it was a good call, as they were a little loose & could use adjustment. Needed several odds & ends gaskets & parts for the R&R of the turbo. No coolant lost or replaced. Tech checked for ECM updates (none found) & made a copy of my ECM parameters on a flash drive for my records. In & out in 2 days. That said, my total bill came to about $2750. Perhaps a little high, but more than I was willing to take on working outside w/o a shelter. Now having my old OEM 160 amp rebuilt locally, kicking it up to the 210 amp rated alternator I replaced 3 -4 years ago so I can have one as a quick back-up for $250 plus he is adding the proper pulley for a relatively easy swap if necessary. Just ordered a replacement Voyager monitor, so I can monitor cameras & my Aladdin system for about $500. Driving old school w/o cameras & only with dash gauges is not too comfortable for me. When it rains it pours sometimes on RV related projects. Thanks to all recommendations & suggestions!

Bart from VA 

2007 HR 42PLQ Scepter w/a GMC 2500HD truck in tow

[BradHend]

Well that could have been much worse.   I’d be quite happy with that outcome.  
Glad to hear you’re back up and running and I have high hopes for those RemFlex gaskets. 
I also was unable to source my manifold, Cummins just said keep calling back. Nothing in salvage market either.    About 4 months later I kinda lost my temper with one of the support people and that’s when they suggested trying an emergency part order but there would be no guarantee, and it would cost money, So I did, and about 1 months later I got a call my manifold was ready to be picked up, their plant in Texas pulled the casting and made one for me.  That was a good day.  Cost me I believe 1800 total just for the larger of the 2 piece manifold.   Smaller one I was able to source.  Crazy.      

Safe travels and happy holidays!

Edited December 7, 2023 by BradHend

[Georgia Mike]

This is a good video on how to remove rusted exhaust manifold bolts 

[jacwjames]

With all you had done it seems the price is fair, too bad you couldn't source a new manifold but using the thicker gaskets hopefully will work?? 

Was there any discussion of having the old one machined?  I did that with a Ford 460 one piece manifold and it's still holding, my mechanics father bought my Class C and it's still working. 

Interesting on the valve job, I asked about this at Cummins shop and they don't do it until 150K miles.   Zmotorsports recently posted on how to adjust, he had more miles but said he's glad he did it early.  So it might be time for me to "Pull up my big boy pants" and tackle the job>>  I've got 125K on my coach.

[Gweedo]

Always replace exhaust manifold bolts.  My manifold was warped 10-thousands, I had it surfaced n reinstalled.   Been 5 years now.     Good luck to you!!!

[isptbart]

9 hours ago, jacwjames said:

With all you had done it seems the price is fair, too bad you couldn't source a new manifold but using the thicker gaskets hopefully will work?? 

Was there any discussion of having the old one machined?  I did that with a Ford 460 one piece manifold and it's still holding, my mechanics father bought my Class C and it's still working. 

Interesting on the valve job, I asked about this at Cummins shop and they don't do it until 150K miles.   Zmotorsports recently posted on how to adjust, he had more miles but said he's glad he did it early.  So it might be time for me to "Pull up my big boy pants" and tackle the job>>  I've got 125K on my coach.

 

Yeah, we looked & unfortunately, no machine shops are still open in our area. To have it sent out of town, machined & returned would tie up their service bay for too long. So my choices were to either put on new standard gaskets on a warped manifold, try the Remflex gaskets or try to purchase another manifold either OEM or aftermarket again with a couple of more days wait. Gaskets installed & works fine - only a longer service term will see if it works long term as designed? Upside - with new bolts & anti-seize should the gaskets fail in a reasonable future period of time, I should have no problem getting them out w/o breaking a bolt! Time will tell.

[dl_racing427]

11 hours ago, isptbart said:

 

Yeah, we looked & unfortunately, no machine shops are still open in our area. To have it sent out of town, machined & returned would tie up their service bay for too long. So my choices were to either put on new standard gaskets on a warped manifold, try the Remflex gaskets or try to purchase another manifold either OEM or aftermarket again with a couple of more days wait. Gaskets installed & works fine - only a longer service term will see if it works long term as designed? Upside - with new bolts & anti-seize should the gaskets fail in a reasonable future period of time, I should have no problem getting them out w/o breaking a bolt! Time will tell.

Your situation is unfortunate.  It would have been much better to mill the manifold flat.
I hope it works out well, and at least it will be a much easier job if there's a next time.

[zmotorsports]

23 hours ago, jacwjames said:

With all you had done it seems the price is fair, too bad you couldn't source a new manifold but using the thicker gaskets hopefully will work?? 

Was there any discussion of having the old one machined?  I did that with a Ford 460 one piece manifold and it's still holding, my mechanics father bought my Class C and it's still working. 

Interesting on the valve job, I asked about this at Cummins shop and they don't do it until 150K miles.   Zmotorsports recently posted on how to adjust, he had more miles but said he's glad he did it early.  So it might be time for me to "Pull up my big boy pants" and tackle the job>>  I've got 125K on my coach.

 

Cummins doesn't recommend performing the valve lash check until 150k so I wouldn't necessarily pay to have a shop do it too awful early as there would still be tolerances.  If you're doing it yourself and can spare the time then by all means as I know a few guys who have checked theirs around 100k.  Personally, from my experience I haven't seen too many that far out by 150k so I think Cummins has a pretty good handle on the mileage recommendation.  Although our coach isn't quite to the 150k mark it is very close after passing 140k this past RV season and I was more concerned about passing the 150k mark mid-next season so I opted to do mine before it comes back out for the 2024 travel season.

 

It really isn't a terrible job but much more invasive and awkward than in an OTR truck where you can stand next to the frame and get to each valve with little effort.  Standing on your head reaching through the closet floor and in and around door tracks and openings does add some time and a bit of frustration but something than anyone who is mechanically minded can do.

 

21 hours ago, Gweedo said:

Always replace exhaust manifold bolts.  My manifold was warped 10-thousands, I had it surfaced n reinstalled.   Been 5 years now.     Good luck to you!!!

 

^^Resurfacing is actually my preferred method of fixing blown exhaust manifold gaskets as long as the manifolds are not cracked or broken.  I have done a lot of exhaust manifolds over the years between gas and diesel powerplants and I always try to save the original manifolds, especially after they have become "seasoned" with tens of thousands of miles and many, many heat cycles as I feel they have already moved around as much as they are going to and hate to start over with new "green" castings.  I would rather take a good used, but warped, exhaust manifold over a new "green casting" any day of the week and twice on Sunday.  I have seen even new exhaust manifolds off by as much as .006" or so and although the spec's generally show .004"-.006" is acceptable and the gaskets will seal, that's too much for my liking.  I end up closing that gap down to less than .002" before I ever install one.  I know many will use much thicker gaskets but I'm also not a fan as it spaces the manifold sealing surface out too far from the head for my taste and creates much more opportunity to blow out after heat cycling.  Personally, I like to keep the manifold as close to the head as possible and do this by truing up the manifold rather than filling that gap with a thicker gasket, but that's just me.  Although a milling machine, or even a flywheel cutter, is the most common piece of equipment for resurfacing, and I have a full machine shop at home, I have found that a flat belt surfacer does a better and faster job of truing up a warped manifold so no need to take it to an actual machine shop as that is a quite common piece of equipment in a lot of shops.

When I first purchased our coach back in 2007 it had an exhaust leak with only 55k miles.  I removed the manifold and found it was warped by around .025" and had three broken bolts and two sections of gasket blown out.  I trued up the manifold halves on my belt sander to within .002", installed new OEM gaskets and all new OEM fasteners and it lasted until the manifold cracked around 115k miles when I had to actually replace the exhaust manifold with a new OEM manifold.  The nice thing about that time was that I had used anti-seize on the fasteners and they all came out without any drama, although I still replaced the fasteners with OEM ones again.

 

I have a video that I show the replacement and even that new manifold I purchased from Cummins was off by a few thou and had to be trued up, which I show how well it trued up in the video where it was closer to .001".

 

[pcpronze]

Here is a test of penetrating oil for you to make your decision.   I had my exhaust manifold gaskets changed this spring at Ronnie's in Elkart and I have 150,000 miles on my 05 Navigator.  and there were no broken bolts.  So I guess it is the luck of the draw or are they prevalent to breakage?  Good luck 

[zmotorsports]

29 minutes ago, pcpronze said:

Here is a test of penetrating oil for you to make your decision.   I had my exhaust manifold gaskets changed this spring at Ronnie's in Elkart and I have 150,000 miles on my 05 Navigator.  and there were no broken bolts.  So I guess it is the luck of the draw or are they prevalent to breakage?  Good luck 

 

Without watching the video I can say that in the 35+ years as an Industrial Maintenance Mechanic and automotive & powersports mechanic I have tried a multitude of products, several of the ones in the picture/video above.  I even used a mixture of acetone and AFT with some success.

 

While from my experience all did a fair job and obviously some better than others, the one I keep in my tool cart and reach for the vast majority of the time is Aerokroil (Kroil).  They claim it's the fluid that creeps and it does in fact do that.  It will penetrate better than anything else I have personally tried.

 

Now I need to watch the stinkin' video and see what they think and hope I didn't make a fool of myself. 🤣

 

 

**Also, while we're on the subject of valve lash adjustments, I haven't done as many as some full-time heavy truck mechanics because I work on such a wide range of powerplants, but I have done probably close to 100 valve adjustments in my 35+ years, between motorcycles, automotive, diesel and power generation and I can count on one hand and have fingers left over how many I have found loose valves on.  They almost always will be on the tight side rather than the loose side.

Reason being is that as the valves open and slam shut, they will impact the seat which will do two things, one it will ever so slightly alter the sealing surface of the valve by some wear and secondly, because it will hammer the seat into the casting of the head.  This will show more prevalently on the first adjustment than subsequent ones because the castings when new are "green" and take many heat cycles to become seasoned.  The second, third and so on I have found less adjustment necessary, but mainly on that initial check is when I have found them to be a couple/few thousandths on the tight side.  

 

In order for the lash to be loose, it would have to point to one of two things, either wear in the valvetrain, or a jam nut has backed off allowing the lash to increase slightly.  In order for that much wear to occur, there would have to be some reason such as neglected preventive service intervals (oil changes) or something wearing to the point that it should be questioned.  I had read and heard about several CAT C7's and a few ISC's over the years that people have found loose jam nuts on their initial valve lash adjustment and on one RV forum (can't remember which one) someone had dropped a valve and upon investigation during teardown, they found several jam nuts loose on other valves where the clearance was excessive, pointing to the possibility of an improper torquing of the jam nut from the factory.

 

Edited December 8, 2023 by zmotorsports

[Kenster]

A friend of mine recently paid $1,400 to have the exhaust manifold gaskets replaced on his isl400. Another friend, just last week paid $38 for new Cummins gaskets and did it himself in less than a day. I have done numerous exhaust gasket changes on Cummins and cats. You do not need to remove the exhaust manifold bolts. You simply loosen all 12 bolts approximately 2 to 3 turns, and then using a small bar try the exhaust manifold out about a quarter of an inch. You then remove both Bolts from one port at a time allowing the gasket to drop out. Do not do all six ports at the same time. If necessary, you can take a hacksaw blade or other thin scraping instrument and scrape the port and exhaust manifold Port clean. You can now hold the gasket in place and insert one Bolt at a time and turn back in approximately one or two turns. Do not tighten the port completely to the head. After you have completed this to each of the six ports, you can retorque the exhaust manifold for the specs.

[zmotorsports]

53 minutes ago, Kenster said:

A friend of mine recently paid $1,400 to have the exhaust manifold gaskets replaced on his isl400. Another friend, just last week paid $38 for new Cummins gaskets and did it himself in less than a day. I have done numerous exhaust gasket changes on Cummins and cats. You do not need to remove the exhaust manifold bolts. You simply loosen all 12 bolts approximately 2 to 3 turns, and then using a small bar try the exhaust manifold out about a quarter of an inch. You then remove both Bolts from one port at a time allowing the gasket to drop out. Do not do all six ports at the same time. If necessary, you can take a hacksaw blade or other thin scraping instrument and scrape the port and exhaust manifold Port clean. You can now hold the gasket in place and insert one Bolt at a time and turn back in approximately one or two turns. Do not tighten the port completely to the head. After you have completed this to each of the six ports, you can retorque the exhaust manifold for the specs.

 

Yes, that is one way to do it.  However, much of the time the gaskets blew out because the manifold warped creating uneven forces.  

Getting to the fasteners and removing them out is hard part.  Personally, after going through all that work there is no way I would not pull the manifold, true it up, run a tap through the holes in the head to clean them, run some Scotchbrite over the head's mating surface and then and only then reassemble and torque everything to spec.  But that's just me.  

[96 EVO]

Yeah, that's what I was thinking!

Could be done, but you'd have no idea how true the manifold is!

[Ivan K]

Not an ISL but I have just recently done all the above on an ISM, 3 piece manifold. Yes, even Cummins manual mentions the one-at-a-time gasket replacement method but I can only see it as a temporary emergency procedure because there is just no way to clean the old gasket remnants off of the head and manifold in a motorhome the way it is mounted right below the intake. BTW, the only studs that needed some penetration help were the 4 on the turbo mount. It also reminds me why I hate driving in the rain...

[96 EVO]

Ivan, where I live, driving in the rain isn't an option 😄!!

[isptbart]

8 hours ago, Kenster said:

A friend of mine recently paid $1,400 to have the exhaust manifold gaskets replaced on his isl400. Another friend, just last week paid $38 for new Cummins gaskets and did it himself in less than a day. I have done numerous exhaust gasket changes on Cummins and cats. You do not need to remove the exhaust manifold bolts. You simply loosen all 12 bolts approximately 2 to 3 turns, and then using a small bar try the exhaust manifold out about a quarter of an inch. You then remove both Bolts from one port at a time allowing the gasket to drop out. Do not do all six ports at the same time. If necessary, you can take a hacksaw blade or other thin scraping instrument and scrape the port and exhaust manifold Port clean. You can now hold the gasket in place and insert one Bolt at a time and turn back in approximately one or two turns. Do not tighten the port completely to the head. After you have completed this to each of the six ports, you can retorque the exhaust manifold for the specs.

Now that my manifold was properly removed & cleaned, with new bolts w/anti-seize, it would be a fairly easy swap for the gaskets - except the manifold is warped at port #3. I would have a chance for an easier removal & swap for a new replacement manifold or possible milling, if necessary?

Bart from VA

[Ivan K]

3 hours ago, 96 EVO said:

Ivan, where I live, driving in the rain isn't an option 😄!!

Hehe, I know Ben, I spent 2 years in Vancouver, in the 90's 🤣

[Gweedo]

7 hours ago, isptbart said:

Now that my manifold was properly removed & cleaned, with new bolts w/anti-seize, it would be a fairly easy swap for the gaskets - except the manifold is warped at port #3. I would have a chance for an easier removal & swap for a new replacement manifold or possible milling, if necessary?

Bart from VA

Look for an old school parts house, some of them will have a flatbed belt sander.  They use this to surface cylinder heads and exhaust manifolds for the local automotive repair shops.  Or ask around some local shops to see if they have the equipment or if they know of another shop.  You may have to drive a little bit.  I am a strong proponent of resurfacing and thinner gaskets,  like I mentioned above mine was way out and it's been about 20k miles now.     This thread makes me want to find used one and have have it surfaced to have on hand for the next time.  Check to make certain of the torque specs when using a lubricant for any consideration.  You're halfway there, all down hill from here.  

[Patrick Roman]

I’ve done this repair on my 2005 Windsor with the 400 Cummins and used a penetrating lube called DeepCreep it works great multiple applications before you start the job ..once I removed the manifold I sent it to an engine machine shop to have it refaced and was badly warped since then it’s been fine  

[wamcneil]

On 12/8/2023 at 8:28 AM, zmotorsports said:

…especially after they have become "seasoned" with tens of thousands of miles and many, many heat cycles as I feel they have already moved around as much as they are going to and hate to start over with new "green" castings….

That’s my feeling. I’ve been really surprised to find how much a new cast iron manifold can change very soon after being put in service. Much better IMO to flatten an old manifold. And I feel like thicker gaskets are a bandaid approach. 
 

[jacwjames]

1 hour ago, wamcneil said:

That’s my feeling. I’ve been really surprised to find how much a new cast iron manifold can change very soon after being put in service. Much better IMO to flatten an old manifold. And I feel like thicker gaskets are a bandaid approach. 
 

I'm sure it depends on engine & application. 

I bought a new Class C in 1997, within ~7 months I had the passenger side fail, developed a crack.  Had it repaired under warranty, which took ~4 months because at the time Ford was having trouble with the manifold across the country.  I called customer service myself and the rep did an inventory check and she confirmed none in inventory.  So ~4 months later finally got the motorhome back.  Asked Ford for an extension of warranty bu was denied. 

Then after one trip the drivers side manifold did the same thing,  had a crack and he exhaust was hitting the wiring harness and fuel line attached to the chassis rail.   Luckily caught it before major damage.  Out of warranty so I changed it myself using an after market manifold which appeared much beefier!  It is still in the Class C. 

About 6 months later the passenger side warped, this was the OEM manifold replaced under warranty and was supposedly a new and improved version.  I took it off and had it machined figuring it had found it's happy place.  Still in the Class C.

 

One issue I had with the Ford 460 in the Class C was that it created a lot of heat on the dog house, I'd burn myself it I let my foot touch the side of it.  I even took the Class C to the nearest Ford shop that could work on it and had them do tests to make sure everything was good.  The shop foreman said the 350 chassis was known for this problem and recommended I buy and a couple fans and mount underneath to blow air across the engine.  Instead I decided to cut a couple of ~2.5" holes in the front scoop under the bumper and route some flexible tubing close to the engine and then used metal flexible tubing to get close the manifold on both side.  It did help cool and didn't have another manifold problem.

[isptbart]

7 hours ago, wamcneil said:

That’s my feeling. I’ve been really surprised to find how much a new cast iron manifold can change very soon after being put in service. Much better IMO to flatten an old manifold. And I feel like thicker gaskets are a bandaid approach. 
 

wamcneil - with my limited options at the time (as described in my update to everyone), all I can hope for is my bandaid approach decision is successful. Time will tell.