ISL Exhaust Manifold Leak - How far can I drive it?

Smitty77 wrote:
Hi Ray - Was that with your current CAT? Or a different coach/engine.

Our old exhaust manifold, and the new one, were two piece. 4 & 2 being the breakdown.

I told the DW, that if I had had any feel that this was going to happen soon, I would have researched in advanced for a 'header' type exhaust manifold. And I admit, I do not know of sure if diesels and gas engines respond the same to improve breathing from headers. But, my basic knowledge is that any engine that breathes better, performs better:)!

At what price, and for how much, is the question.




If a 'header type', improved exhaust manifold, can/could increase power output by 5 or maybe 10% - then I would have prepared better for this 'opportunity!'.

I have seen some 'Diesel Performance Improvement' Exhaust Manifolds - but have never researched them. My options were limited on this one, due to needing to get a healthy engine back on the road.

And I never lose site that Cummins engineered an impressive mid size block engine, to serve many customers. The RV'ing community was a relatively small percentage of the target market for the ISL (Or any Cummins engine.). Suspect the ISB is the exception, due to the high qty going into the Doge trucks, and a much smaller overall number of RV's.

It's a done deal now, as I doubt I'd toss away the new Exhaust Manifold now, unless I could guarantee at least a 10% increase in power for under $2K - and heck, while dreaming, toss in a 2-3 MPG improvement too:)!

Best to all,
Smitty

Smitty: The manifolds that were changed out was on the Caterpillar engine on my current coach.

Hi Ray - Was that with your current CAT? Or a different coach/engine.

Our old exhaust manifold, and the new one, were two piece. 4 & 2 being the breakdown.

I told the DW, that if I had had any feel that this was going to happen soon, I would have researched in advanced for a 'header' type exhaust manifold. And I admit, I do not know of sure if diesels and gas engines respond the same to improve breathing from headers. But, my basic knowledge is that any engine that breathes better, performs better:)!

At what price, and for how much, is the question.

If a 'header type', improved exhaust manifold, can/could increase power output by 5 or maybe 10% - then I would have prepared better for this 'opportunity!'.

I have seen some 'Diesel Performance Improvement' Exhaust Manifolds - but have never researched them. My options were limited on this one, due to needing to get a healthy engine back on the road.

And I never lose site that Cummins engineered an impressive mid size block engine, to serve many customers. The RV'ing community was a relatively small percentage of the target market for the ISL (Or any Cummins engine.). Suspect the ISB is the exception, due to the high qty going into the Doge trucks, and a much smaller overall number of RV's.

It's a done deal now, as I doubt I'd toss away the new Exhaust Manifold now, unless I could guarantee at least a 10% increase in power for under $2K - and heck, while dreaming, toss in a 2-3 MPG improvement too:)!

Best to all,
Smitty

The three piece manifold on my coach was replaced with new equipment, new studs and gaskets. I did not want to take a chance on a warped manifold that could give problems later on. So I had them replaced, plus since the coach was in the Freight liner shop in Las Vegas I also told them to replace the filters on the air dryer. I also wanted the serpentine belt changed, but they said that there was nothing wrong with the belt that was on, so I bought the two belts to carry on the coach.

Total bill was $2400. So for all the work they done I did not think it was bad.

icehip - We did find a good group to work with, and this goodness was reflected for in the shop rate charged. (Not a dig, and though of course I'd rather have the lowest bill possible. I'm more concerned with quality and a proper repair, the the lowest possible cost.).

Yes, even though trying to describe the condition of our manifold in my last two posts. (Should never try to type on a small phone - as I'm all thumbs:)!) We had a 11 year old engine, and I'm glad that this did not snowball as the mechanic did his thing...

On the re-torque of the exhaust bolts with a new green casting. I've had PM's that said to do the re-torque, and ones that said not too. When i called Cummins, the tech support gents comment was: "Do you think that all of the cars, trucks, RV's, Etc. sold new - have their exhaust bolts re-torqued after a period of time?".

Well of course the don't. But, I'm kind of planning to get a couple of more heat cycles on this exhaust manifold, and then check any of the bolts I can reach without tearing apart the bedroom - again. If any of them seem to have needed the extra touch up re-torque. Then I'll do what needs to be done to get to the rest of them too...

Best,
Smitty

Smitty77, consider yourself very fortunate to have found a decent shop.
I had a warped exhaust manifold replaced in Tucson and was hosed $2225 for labor and $767 for parts last APRIL. This did include time to replace a rusted drain valve on the rad found when attempting to drain the antifreeze and replacement of the coolant line from the head to the turbo which broke during removal. Only one broken bolt an cylinder 3 to extract.

It was not warped, and more importantly, ****ed at an angle. So even if I had run it over to a machine shop, the '****ed' #3 would have pre-loaded the bolts (If the manifold holes on of #3 would aligned with he bolts).

Well I used the wrong words, as it was **** out:)! And I also said 'not warped', when i should have said it was warped. But the key, was that #3 exhaust was twisted at an angle, that even with excessive machining of the exhausts, would have still been highly unlikely to line up with the #3 bolts.

Sorry for the wrong choice or words... Still wondering if I should re-torque down the road?

Best,
Smitty

Well it was a pretty straight forward day. We had the back opened and ready for the mechanic, and they started promptly at 7:30AM. By 9:15AM they had the exhaust manifold off, with two broken bolts (the one on #3), and on the bench for us to all look over. It was not warped, and more importantly, ****ed at an angle. So even if I had run it over to a machine shop, the '****ed' #3 would have pre-loaded the bolts (If the manifold holes on of #3 would aligned with he bolts).

So, new manifold, bolts, turbo bolts, gasket - and back out of the shop by 1:00PM. (With sometime for the mechanic to have lunch in this time.)

I asked on another board, whether or not anyone knows if I should re-torque the bolts after some heating/cooling cycles have gone by. Maybe a few thousand miles? (The Cummins shop said they were not advised by Cummins to do this. But both the mechanic and Service Supervisor both said they could not see how it would hurt to do so. Mostly just 'tighten only' not loosening and then torquing again.)

Any input on if 're-torquing' and if so, how far before doing so?

Rocky Mountain Cummins at Grand Junction did what they said they would do. Did a professional job. Run a real clean, and safe, shop. Very efficient office staff. Looked to be a former Coach Care facility, but not sure. Value? Well, the shop rates not only cover the mechanic, but this professional staff that I just mentioned. It's one of those things where you are paying for the Cummins expertise, in a location where you should expect (and did in this case) efficient experience. Lower costs shop rates shops are available, and 'can' provide good care too. But when you're on the road, and have reservations with penalties along the way. Getting in, and getting out - with proper repairs, is what you should expect to get for these higher shop rates:)!

Best to all,
Smitty

I had tried to remove exhaust bolts on my 5.9 Cummins to replace gaskets and soaked them in penetrating oil with the first two breaking off. All the bolts on this engine have an exposed center part so I then ran the motor until the manifold was good and warm and put an ice cube on the open part until melted then each bolt came off with no problems.
If you can heat the manifold then cool the bolt somehow it helps greatly in being successful.
The two that broke off were replaced with a slightly larger bolt and nut as there was room to use a nut. Good luck to all. Doug

Thanks for the continued feedback!

And ouch, and crossed fingers, on all the parts you needed Snomas!

Wolfe10- Yes to a seasoned casting is a known item. But, it is supposed to also be a new and improved manifold, as well as gasket. And who knows, it may not be warped (Wink, pretty good chance that it is...). Rocky Mountain, and most Cummins shops, prefer to toss new parts at a repair. But, if it is not cracked, and not too badly warped - I'll sure go over this with the Service Manager.

We'll see.

Best to you both, and thanks,
Smitty

We found we had a manifold leak on our way to Denver about 3 yrs ago and drove about 400 mi after the find. When we got to Denver Rocky Mtn Cummins had to do the following to fix. New exhaust manifold, new head, new turbo charger, new injection fuel pump & fuel lines. Cost about 12K. Hope you don't have all these type of problems!