If the car is brush-based, make it a func_wall_toggle, "start invisible" or whatever. On the monster, set "TriggerTarget" to the car's name, and "Trigger Condition" to "Death".
Hehe, thought I'd start a bug thread, there're bound to be some with all the new coding. Like the one where I deleted all of my journal entries and can no longer create them ("This member has not written any journal entries") lol. I knew I was tempting fate when I deleted it