Could a gasoline's octane level affect radiator performance?

So I have a '96 Honda Civic VTI. I've been using a 95 octane gasoline from Petron, then as advised by a friend who has a similar car, I switched to 97 octane gasoline from Seaoil.

After a few weeks I made the switch, my car had several problems - hard starting, variable revs when going above 3000 rpm, and the most peculiar one is that the water on my radiator and reserve is constantly draining, regardless if I use the car or not. If I park it for a day, the water reserves are drained, faster if I park it outside, on direct sunlight.

Now I went back to using 95 octane from Petron, now the hard starting is gone, revs are good and I haven't refilled my radiator in 2 days now.

Could there be a connection between th issues I had with changing the gasoline?

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