One problem related to engine noise has been reported for the 2003 Toyota Highlander. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 Toyota Highlander based on all problems reported for the 2003 Highlander.
I noticed that the engine noise changed. Took the SUV to the dealer to check it out, dealer stated that the noise was ok and returned the vehicle to me. After driving the vehicle less than 10 miles returned it to the dealer and the engine was blown.