ORIGINAL: blw
No, castor doesn't displace water, but it protects the metal surfaces from rust.
If you read about bearings for a while on RCU, you will find that the rust problem is illogical at times. Members have rust issues often when they do everything right to prevent it. Then, people like me don't do a thing and never get rust.
Castor is probally one of the best oils when it comes to protecting a running engine, however it does not make a good oil for protecting a stored engine, it will end up turning into gum and creating a mess . ATF will actually stay fluid and prevent any moisture from attacking the inside of our engines. Not too mention atf is much cheaper to buy as well.