All,
Continuing to invest in the coach this month...
On another issue my mech uncovered a leaking exhaust manifold. I had been hearing something unusual back there.
Mech says he will work 8 hours and only charge me 4, a new Cummins exhaust manifold w/gasket kit = $600 USD. Mechanic has big diesel business and has a 6CTA8.3 on his yard out of a truck a client needed the dump bed off of and he will sell me the exhaust manifold for $100, this includes his labor to remove the manifold and he will sandblast it.
My current and leaking exhaust manifold is -very- rusty. The used one on the parts engine is not nearly as rusty. Any opinions on buying the used manifold, sandblasting it and then having the used/sandblasted used manifold ceramic coated.
So, basically I can have a used manifold in good condition, sandblasted and ceramic coated for about $200 plus the gasket which must be about $100. If I get the new one I will ceramic coat it as well for an additional $100. So: good used/sandblasted/ceramic coated w/gaskets about $300 and new one sandblasted and coated about $700. Is the $400 savings wise??
Appreciated informed opinions. I lean toward the used one, but don't want to make a foolish mistake for $400.

I would go used. A new one can crack as eazy as used one.

Same here - for the difference in price, there's not a corresponding difference in expected service life.

I have no diesel experience, but with gassers, a used manifold can be better, as it is seasoned and less likely to warp.

I don't know if this engine ever cracks manifolds, but if it does, I would have it dye-penetrant checked. Surfacing it would assure long gasket life.

I also like to spot-face the washer surfaces and use hardened washers so expansion is smooth. A little graphite compound under the washers helps, too.

Be sure to post a picture of the ceramic-coated manifold. Jaguars used to come that way. Quite nice.

I don't know if thats a 1 piece or a 3 peice manifold but with a 3 piece they crack because the joints freeze up in the joint with rust and they can't expand with heat,it also causes manifold bolts to break also.

All,
Thanks for the input. This is the 1 piece manifold. I was leaning toward the new but you boys are steering me toward the used. I appreciate all the input. Where would we be with this forum??
The ceramic coating looks to be the ticket for sure. I suppose the factory won't do it for they don't have to, but the data seems clear that it will easily double the life of any exhaust system component by simply killing the chance for oxidation. You can do it your self and cure it with the exhaust gasses when you start up or have a local shop bake it to cure it in a big oven. I hear the engine running curing method works well. I just did this with a cracked muffler/muffler pipe on my lawnmower. Worked great, looks great, no chance for rust.
Thanks again.
Thanks again

I replaced my manifold on the B5.9 Cummins last year with a new one because it was cracked and the leak was getting worse. I had previously replaced the exhaust gaskets as a couple of them were blown thru when I first got the Barth 3 years ago.

Here is the write up I did after the change:

Exhaust manifold change

I can't say the same issues are present with the 8.3 engine but the manifold on the B5.9 has been changed a number of times to decrease the likelihood of cracking. I also found that the old manifold had shortened quite a bit in comparison to the new one. In fact it was so short that the end manifold bolts were binding as I backed them out. The new manifold has shortened since I have put it in and I am watching it.

The cost at the Cummins parts shop for the manifold was $145 new. Don't remember the cost of the gaskets. Again the 8.3 engine may be a bit more expensive.

Ceramic coating may help a bit with heat but these are cast manifolds and will not be effected by oxidation, sure it is there and looks bad but that isn't the cause of issues, cracking is. Ceramic coating will get more heat to the turbo and give better boost at lower RPM. Not sure if the ceramic coating will delay or reduce cracking issues.

I ceramic coat my race engine headers but they are fabricated with steel tubing, increases turbo response and also reduces under hood temperatures.