One problem related to engine cooling system has been reported for the 2003 Mazda MPV. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 Mazda MPV based on all problems reported for the 2003 MPV.
The car was operating normally, than the water pump broke. This caused the engine to overheat. The waterpump was replaced and the engine required a valve job.