[tomj76]

I completed the job. Getting the bolt out wasn't quite as difficult as I expected. I used the "dremmel tool" to cut a slot in the head so that my punch had something solid behind it at the right angle, then used a hammer on the punch to turn the bolt. After it was started it came out easily.

There was a lot of hard carbon build-up in the intake passages ~30 mils thick, so I tried to clean that while I had it apart. There wasn't much evidence of oil sludge in the water passages, so I think my sludge is only in the radiator. I didn't have time to flush the radiator while I had it drained, so that's a job for another day.

The installation was more interesting, as I had issues with continuous misfiring on #6. I checked & cleaned the plugs of carbon and oil, but that didn't cure it so I swapped the injector to see if the problem moved with the injector. I had swapped #4 with #6 during installation anyway. It started running without the misfire at that point, but now I'm getting P0401 (low EGR flow) that I've traced clogged DPFE ports on the EGR pipe. They are filled with dry carbon, no exhaust flowing with the DPFE hoses removed. Being curved, I can't use a drill bit to open them up around the corner.

I'm also not completely sure that I've got a good seal on the intake, as the scan tool reports LTFT at idle that is +8% on bank 1, and +12% on bank 2. Bank 2 is where I had the coolant leak before starting. That said, there is a lot of carbon in the exhaust while I let it idle (implying a rich mixture, in conflict with the computer). Once I get the DPFE ports working again, I'm thinking that I may have excessive build-up on the O2 sensors.