replace 6V92 exhaust manifold
If you have a 6V92 with a crack in the exhaust manifold here's some information that's not in the service manual but you'll find it valuable. Be sure you've got the correct exhaust manifold and gasket before you start. Hold it up to your current exhaust manifold and make sure because there are different exhaust manifolds for the same engine. If this is your first time doing this start in the morning so you've got plenty of time. It's actually a pretty straightforward job if you've done it before, but if you haven't you'll need to figure out some stuff along the way. You'll need to be physically flexible to do this job. You have to lie down on top of the engine so you'll need coveralls, and kneepads would make it more comfortable. I replaced the exhaust manifold on the passenger side so in my case I had to remove the crossover pipes from the air filter to the turbocharger intake, from the exhaust manifold to the turbocharger, the oil filler from the back door to the valve cover, and the crankcase breather tube from the valve cover to down under the coach. There are only four nuts to remove from the exhaust manifold into the cylinder head. They require 11/16" sockets in both standard and deep well lengths and a wobble socket with a universal joint in the middle. The cylinder head puts the nuts at a weird angle and the frame rail is close to the exhaust manifold. It would be better to use a 3/8" drive ratchet to fit into the tight space. Follow the instructions in the Detroit Diesel service manual exactly. Be aware that the studs will probably come out of the cylinder head, which the service manual doesn't mention, and they're wet holes, so have about 3 gallons of the correct antifreeze on hand to replace the coolant you're sure to lose on the ground. If you're using 50/50 antifreeze double that figure. Have some RTV on hand to put on the threads of the studs that come out of the cylinder head before you reinstall them. Remove the nuts from the studs and clean the threads of the studs before you reinstall them so you get the correct torque reading when you reinstall them. You probably already knew that but it's not mentioned in the service manual. You can put the special washers and nuts on the very end of the studs after you install the new gasket and they'll prevent the gasket from falling off while you slide the manifold down into position. Follow the service manual's instructions exactly and be sure you get the gasket facing the correct direction. Slide the exhaust manifold down onto the studs, being careful to get the gasket between the exhaust manifold and the cylinder head without damaging it. The exhaust manifold is slotted so you can just slide it down onto the studs even with the nuts, washers, and gasket already on the studs. The service manual doesn't tell you this next part but it's important. Before you start tightening the exhaust manifold to the cylinder head install the exhaust crossover pipe from the exhaust manifold to the turbocharger or else you won't be able to get it aligned properly. As you tighten the exhaust manifold to the cylinder head you have to push down on the exhaust manifold so the tabs cast into the bottom of each end of the exhaust manifold bottom out. If you don't do this the exhaust manifold won't align perfectly with the exhaust ports in the cylinder head and the gasket may leak. You mainly need to push down on the end of the manifold towards the front of the coach because the weight of the crossover pipe tends to hold down the end of the manifold towards the back of the coach. Do I need to post a photo of these tabs cast into the bottom of the exhaust manifold or do you guys understand what I'm trying to say? Now go back to following the service manual exactly for the rest of this job paying particular attention to the torque specifications, which special nuts go on which studs, the direction the special nuts face, and the order in which you torque the studs. Yeah, it really is only 35 ft lbs of torque. I did a double take on that myself. A 3/8" drive torque wrench with a flexible head that can bend at a shallow angle will be very helpful. You may be able to rent one from NAPA or O'Reilly if you don't have one. When reinstalling the crossover from the air filter to the turbocharger you may have to clean the corrosion off the ends with a wire brush and put some grease on the ends to get it to slide back into the fittings. If you have questions please ask. Sooner would be better than later while this is still fresh in my mind! 
Topic: replace 6V92 exhaust manifold