My '99 F350 finally let me down...the V10 sheared off three studs at the rear of the driver's side exhaust manifold. Manifold warped, gasket blew out, LOTS of noise, oxygen sensor very confused...
Passenger side isn't leaking yet, but it has already lost one stud. Just looking at this job is enough to make me cry, everything will need to be heated, studs drilled out, ugh. I managed to find someone that has done quite a few of these jobs and is confident they can handle it, but the parts are still pretty pricey. I dropped the truck off yesterday, with any luck it will be back in action in a few days.
I did not take any "before" pictures, but I will post some when things are buttoned back up. I blame the failure on a crappy design and 14 years of Northeast winters. Being a plow truck, those manifolds have sure been blasted with a lot of slush and water loaded with salt. The manifolds are longer than average (5 cylinders), and do not expand/contract at the same rate as the aluminum head. There is no expansion joint in the manifold like a lot of commercial engines use, so the expansion puts a lot of stress on the very small studs. I bought Dorman (aftermarket) manifolds for the repair, and it was nice to see that they have slotted the holes at each end of the manifold. The center holes fit tightly on the studs, but as you move left or right the holes are larger and/or slotted...allowing for some movement.
One thing worth mentioning, the mechanic said a lot of people run the truck way too long with a leaking manifold. He has seen some where the aluminum mounting surface on the head gets etched.