The Auto-Rx will not damage your engine in any way. It is a natural cleaning agent and will slowly clean your engine. That is why I mentioned the HEUI injectors in my engine, they take up to 3000 PSI to activate, and the Auto-RX has no effect on this. It does not change the viscosity of the oil. The only thing is to follow the cleaning instructions for an engine with leaks. I would start with clean dino oil and filter, but not required. The Auto-Rx should help your leaks if the seals are not damaged. If they are, and the leaks don't stop, you will have a clean running engine.
I have put Auto-Rx in a new PSD, mine, new 03 Mazda with 100 miles on it and my own Mazda. No problems. It works as stated, cleaned the engine and now I just use a Maintenance dose. I will probably never have to clean them again at this rate.
Tony