Xbox One S turns off after loading online game then won't turn back on

My daughter spilled soda into her xbox. She immediately turned it over so it would drain out and all seemed well. A few days later it started shutting down as soon as she loads an online game. I took it apart, cleaned it, replaced the fan (it was all dusty and sticky), cleaned the heat sink and put it back together. It’s still doing it. After sitting for awhile it will turn on, connect to wifi, and load her game - then immediately shut off and not turn back on until it sits for a while. No error messages or other indication that anything is wrong. Should I replace the heat sink (it was pretty sticky as well)? Internal Power supply? Could it be the WiFi card? I also noticed that only cool air seems to be coming from the vent. Thanks in advance!