radiator tank leaks

[vtmbz]

I'm seeing a small amount of weeping on the top of my Behr radiator tank; where the aluminum and the plastic side tank join. This is original radiator I feel certain.

Im in a cool climate with little stop and go driving; wondering if I can replace the radiator cap with a lower pressure one instead of buying a new radiator.

The car runs around 90c all the time, with long hills going to 100c.

Would less pressure make any difference?