My toilet makes noise like an airplane taxiing for takeoff, from the moment the flush handle is depressed until the tank is refilled. The toilet is in my vacation home, so it's not in constant use, but the problem has persisted for several months.

Which ballcock id yours?

I think it's the one on the left, but I'm not at the house, so I can't check - it's about two hours away. It's new house, built about 3 years ago. Does that make it more likely that it would be one than the other?