I had the axles out for a preventative rebooting, so that helped with access & clearance. I was able to undo the single mount-to-subframe nut from below & jack the engine up a couple inches, just till the exhaust collector was touching the frame. It was very tricky to position a wrench on the mount nut with the exhaust in place. There is a thick washer under that nut, so watch for it to fall & remember to put it back.
There’s little room to work near the upper end of the pipe. You need to get in there to separate 2 hoses (1 to throttle body, 1 to heater) & to remove its bolt. I ended up removing the other heater hose to gain access, so mark them to ensure you don’t switch them.
I removed the battery & the black metal cover over the fuel injectors for more maneuvering room. I finagled the old pipe & removed it from above. The new one went in similarly.
At least for gen3 H6 owners in the salt belt, if not everywhere, it seems that this pipe should be routinely inspected. There’s a similar looking pipe on gen2 H6 models that may present the same issue. It doesn’t look like H4 cars have this pipe & it does look like the 3.6 H6 has a similar pipe.
There’s a 2nd coolant pipe heading from the thermostat area over to the oil cooler assembly, that may also have some rust. I chose to replace mine while I had easy access. This pipe is shorter & less bendy but for some reason costs double the other pipe.
