My thoughts on stop leak type additives...what else is it going to stop in the system. It might work, then again, it might backfire and stop the whole system from operating, causing additional cost of removing, cleaning, replacing seals and pumps. I think I would continue to add fluid as needed until time/money allows for repair.
You might do a search on YouTube to see if the repair is something you can handle in a few hours, saving you time /money and accomplish the needed repair sooner.
Texas Crappie Posse