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texnet · 08-24-2014, 08:47 PM

A few months ago I had our coach in for service and the tech noticed that the exhaust manifold was cracked. It was a very clean crack 100% around the manifold between the 3rd and 4th port. There were no signs of exhaust leaking at the crack and there were no performance issues. This was and independent truck shop and I respect their estimate but I was not wanting to spend $1700.00 ($800 parts, $900 estimate labor) to get it fixed, so I waited... We made 2 or 3 small trips and I would check the manifold each trip and there was no change.

A couple of weeks ago I got a quote from the Southern Plains Cummins in Fort Worth. $501.36 for parts, $908.oo for labor and $116.34 for tax. I noticed their partts were a little cheaper, so I called them again for a parts only quote. The quote came back the same price for parts.

They had all the parts in stock with the exception of the short manifold, but that was only 25 miles away. I decided I would change the manifold myself and save $900+ in labor.

Today was the day.. I started on it about 3:30pm, finished about 7:30pm, total of 4 hours. I also spent an additional hour cleaning up battery and ground connections and a little cleaning on the engine. While I am one tried guy (67 yrs old in 1.5 months), I am well pleased that I did the job in 4 hours when the shops are quoting 8 hours!

I had worried about broken bolts all week, but I had no problems with broken bolts, or any other issues. However, I did prepare! Each day for the last 6 days I have been spraying the bolts with PBlaster in the morning and in the evening. NONE of the bolts where hard to remove, just the normal 39 lbs they were torqued.

bobandshaz · 08-24-2014, 09:05 PM

Great job. A little prep goes along way.

texnet · 08-26-2014, 12:00 AM

A few have asked, so here is the parts break down for the Cummins ISL 400 exhaust manifold and the prices I paid. I purchased directly from Cummins. I replaced all the bolts, studs and nuts.

3964070 - Manifold, Exhaust - Long ---- $250.99 x 1
3937477 - Manifold, Exhaust - Short ---- $118.79 x 1
5269779 - Gasket, Exhaust Manifold ---- $9.33 x 6
3944593 - Screw, Hex Flange Head Cap - $3.03 x 11
3944655 - Screw, Studded Flange Cap - $6.27 x 1
3818823 - Stud - $5.82 x 4
3818824 - Nut, Regular Hexagon - $2.49 x 4
3945252 - Spacer, Mounting - $3.00 x 12

If you want to remove the Turbocharger then add a gasket, 3901356 which is 4.88. I did not remove the turbocharger.

deandec · 08-31-2014, 07:52 AM

Well done. The preparation with PB Blaster was an excellent thought.

Air Baron · 08-31-2014, 08:02 AM

Good job. Thankfully you are not a full timer on the road, had a place that allowed you to work on it, were able to get all the parts before starting work...and had the option of soaking the bolts for 6 days (more than just a "little" prep) before trying to remove them. I also bet your rig did not spend most of it's 11 years parked in a salt air marina on the east coat, and the engine compartment was not constantly blasted with a water hose.

Coma · 08-31-2014, 08:43 AM

Nice job! I used 50/50 ATF and Acetone. Although I had the job done there were no broken bolts, and no extra $$$ labor.

texnet · 09-01-2014, 07:54 PM

You are correct on all counts I think... However, not sure about the 11 years parked near a salt air marina. This is a 2003 coach, purchased by us as a repo in 2011, so it didn't have 11 years but maybe some of the 8 years of it's life. It was licensed in Florida when I purchased it. I am VERY thankful that I have the God given ability and aptitude to work on just about anything that is put in front of me, from model cars, to electronics, to classic cars to even our motor home

P.S. Since all the work was done inside the MH, even had of I been in an RV park they would have never known I was working on it......

Quote:

Originally Posted by Air Baron

Good job. Thankfully you are not a full timer on the road, had a place that allowed you to work on it, were able to get all the parts before starting work...and had the option of soaking the bolts for 6 days (more than just a "little" prep) before trying to remove them. I also bet your rig did not spend most of it's 11 years parked in a salt air marina on the east coat, and the engine compartment was not constantly blasted with a water hose.

texnet · 09-01-2014, 07:56 PM

Quote:

Originally Posted by Coma

Nice job! I used 50/50 ATF and Acetone. Although I had the job done there were no broken bolts, and no extra $$$ labor.

I did use 50/50 ATF/Acetone the last day

Bob&AnnaMari · 09-03-2014, 09:53 PM

texnet,

Well I am in a similar situation with a cracked manifold and was looking at my setup today. I can see where I have easy access to the actual manifold bolts, but I am left with the question as to how you removed the 4 bolts that attach the manifold to the turbocharger. The bolts on my engine come up from the bottom and have very limited access from the top of the engine. You apparently removed these rather than removing the turbocharger itself. So, my question to you is: "How did you get these 4 bolts out?" I can't see a clear path to getting a wrench in there to remove them.

And I also want to thank you very much for posting your parts list and accompanying prices. I checked with my local OC Cummins parts distributor and they have no problem matching those prices. They further suggested that I join the the Cummins Power Club and save even more. (Like you, I was quoted much, much more by a local repair shop for just the parts.)

Once I get the issue of the 4 bolts to the turbocharger resolved I should be good to go.

Thanks in advance for your help on all this.
Bob

Coma · 09-04-2014, 07:24 AM

Quote:

Originally Posted by Bob&AnnaMari

Once I get the issue of the 4 bolts to the turbocharger resolved I should be good to go.

Thanks in advance for your help on all this.
Bob

FWIW the TC bolts are really studs. Two places to get things stuck, the stud and the nut. Also, one of the manifold bolts is not a hex head, that would be the one really hidden.

If you do remove the TC there is a gasket for the TC oil return. Those bolts must be torqued correctly or you will have a leak…...

Air Baron · 09-04-2014, 11:21 AM

Quote:

Originally Posted by Coma

If you do remove the TC there is a gasket for the TC oil return. Those bolts must be torqued correctly or you will have a leak…...

On my ISC the Cummins mechanic found that the threads going into the aluminum oil filter housing were stripped out...not sure whether that line is oil supply or oil drain. Anyhow, they said it was due to corrosion and not their fault. Cost me another day in the motel because they did not have the housing at the distributorship, as well as $500 plus for the housing and more $120/hr plus labor. Unfortunately, ya don't know what ya don't know.

Coma · 09-05-2014, 07:00 AM

Quote:

Originally Posted by Air Baron

On my ISC the Cummins mechanic found that the threads going into the aluminum oil filter housing were stripped out...not sure whether that line is oil supply or oil drain. Anyhow, they said it was due to corrosion and not their fault. Cost me another day in the motel because they did not have the housing at the distributorship, as well as $500 plus for the housing and more $120/hr plus labor. Unfortunately, ya don't know what ya don't know.

The return line is just a drain back to the block, if I understand correctly. I agree however, that unknowns are part of the joys of ownership.

texnet · 09-15-2014, 07:07 PM

Sorry for the delay in answering your post.. I just answered your PM :-) We have been on the road for the last couple of weeks as a volunteer at a Teen Challenge project with MAPS RV and I haven't checked into the forums... The nuts on the studs were actually easy to get to. I used a rachet box end and a rachet with a socket to get them off. They look like they are hard to get to but once you get in the engine compartment and down to them they are actually fairly easy. Good luck!!

Quote:

Originally Posted by Bob&AnnaMari

You apparently removed these rather than removing the turbocharger itself. So, my question to you is: "How did you get these 4 bolts out?" I can't see a clear path to getting a wrench in there to remove them.

texnet · 09-15-2014, 07:19 PM

An update....

A few days after I completed the installation of the exhaust manifold we left for a trip to Mt. Juliet, TN for a few days, then to Hot Springs, AR for about a week. I had not noticed any problems with the cracked manifold as I assume the crack happened gradually. HOWEVER after I replaced the manifold, I DID notice an improvement with the motorhome. I had about 2-4 lbs additional turbo boost, and I saw an increase of about 1.5 MPG.

So.. I am very pleased that I got that task done and over with. With the increase in MPG the parts will be paid for in no time!