Oil seal break-in time and oil loss

A new seal shouldn't leak at all from the time it is installed. There is no break in time. A seal that leaks is either not installed correctly, the wrong seal or the shaft it is riding on has damage. The normal issue is that the area the seal rides on gets a groove worn in it and the new seal doesn't fit properly because of that and it leaks. For that you can sometimes install the seal just a bit farther out or in so the seal doesn't ride in that groove, another repair is called a speedi-sleeve, that is a thin stainless sleeve you press into place over the worn area so the seal has a smooth surface again. The last resort is replacing the worn part, with a crankshaft the first two options are a bunch cheaper and easier.
Another common reason for seal leaks is a bad PCV system. The crankcase should have no pressure in it but because of blowby from the cylinders it has pressure in it. The PCV system is there to collect those vapors and oil mist and send it to the intake to be burned off. They can get plugged with oil or the hoses get blocked and now you get pressure in the crankcase, that can be enough to cause a leak.
I would check the PCV system first as it may have caused the issue for the first seal.

Good afternoon.

It should stop immediately if it was the seal.

Did you make sure the PCV system is working? If it is not there will be too much pressure and the weakest seal is the rear main.

Did you check the surface of the crank for any grooves? Also, a bad rear main bearing will allow it to continue to leak.

Roy

You are welcome.

Always glad to help.

Roy