One problem related to loud engine noise has been reported for the 2004 Hyundai Elantra. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Hyundai Elantra based on all problems reported for the 2004 Elantra.
I was driving on the highway and suddenly the oil light came on. At the same time, there was a loud noise so I pulled over and turned off my car. Minutes later I tried to turn it on but no life whatsoever. Got out of car and saw big oil spill along the side up to where I drove to. Drove car to mechanic. Engine had hole in the engine block.