I'm planning to rent a car in Argentina by one of the big, well-known companies. I'm also planning to drive to Chile for a day or two. I know that quite a lot of rental companies explicitly do not allow to cross into other countries with a rental car. However, when trying to book a car on one of the big rental car websites, I've almost always have trouble to find information about that point. I don't want to first write them an email or call them. Are there other ways to get this information?

I'm talking about Europcar, Hertz, Budget, Avis, and Sixt.