After completing your paperwork at the car rental company, you should examine the vehicle in detail with the officer and report any scratches or cracks. You will not be held responsible for previous defects by having even the smallest defects reported. You should open all the doors, trunk and hood of the vehicle and check if there is any problem in the mechanisms. If the rented vehicle breaks down, will it be replaced? If the vehicle you rented breaks down, you should contact the car rental company. The company will send a new one to replace the defective vehicle as soon as possible.