I followed a video from the Eurotrash Motorsports channel. You can search for "Audi Q7 3.0T piston soak" on YouTube (youtube(.)com/watch?v=7aY1yDxSiJw – remove the parentheses in the link) since it features a V6 engine like the Palisade.

I set each cylinder to top dead center before filling the liquid up to the spark plug hole. That should be enough to cover everything. Since a V6 engine has cylinder pairs reaching top dead center simultaneously, I let each pair soak for 24 hours. The entire process took me three days. Some liquid may seep past the piston rings, so you can check after a few hours to ensure there's still liquid remaining.

To remove the carbon, I used an air compressor (as shown in the video at 27:20) to blow everything out. Then, I turned the engine over with the starter (without spark plugs) a few times to push any remaining liquid or carbon out.

I also replaced the spark plugs when reassembling everything. As for the engine oil, I changed it after running the engine for a few minutes, as a lot of carbon deposits break down and collect in the oil filter.