This probably not the correct form of this type of question, but here goes.
The Cessna Pilots Association has a very good Technical Support organization so as a Cessna owner you might consider joining them. If you can't find them send me a PM.
For my part of this and an A&P/IA I would think that you have some pressure in the pushrod tube that is pushing the seal off. Or, the tube and the seal are worn out. What is the compression on that cylinder?? When you check it take the rocker cover off, and listen for leaks.
Speedbird48.