One problem related to water pump has been reported for the 2004 Toyota Sienna.
The most recently reported issues are listed below.
Please also check out the
statistics and reliability analysis of the 2004 Toyota Sienna based on all problems reported for the 2004 Sienna.
1 Water Pump problem
Failure Date: 12/11/2010
My 2004 Sienna has leak in water pump with 66k mile.
Other Engine And Engine Cooling related problems of the 2004 Toyota Sienna