One problem related to radiator has been reported for the 2003 Toyota Matrix. The most recently reported issues are listed below.
The air conditioning started to blow hot air, then the engine started stalling and the engine check sign came on. Toyota said it was a stone that got into the radiator and provoked a leaking. No signs of damage in the front bumper. How can a stone get there and how do they make such fragile cars? I had to pay for the damages although it is a brand new car.