Finally got the results from the auto repair shop. Nathan's radiator has a crack in it, hence the several-month saga.
The good news: it will be fixed today.
The bad news: it's relatively expensive. They have to actually replace it.
I can't wait for the lawsuit settlement to come through for his car accident. I hope it's enough to purchase a newer car. I'm very grateful for the free (except for the repairs) car he's driving, but our cars are quite a bit older and I'm getting tired of budgeting for so many repairs. There goes my overtime $$.