One problem related to loud engine noise has been reported for the 1997 Ford E-350. The most recently reported issues are listed below.
My v10 Ford E-350 motor had a head failure and a spark plug blew out while driving. A fire started in the engine compartment and the explosion sound created a panic and startled response that almost lead to a vehicle crash. The vehicle was towed to a repair facility and they were familiar with the problem. They work on fleet vehicles regularly and they stated they have seen this problem many times before. The aluminum head of the engine was too weak to hold on to the spark plug and that lead to the explosion, fire, and damage. The shop informed me that this could very likely happen again because of the defective design of the engine and if I am traveling with my family I could be left stranded, possible a very dangerous part of the highway while driving steep or dangerous roads. If the vehicle catches on fire again it could explode if the gas line ignites. This one cylinder cost $800 to fix but now I have 9 other ones to worry about. I was not able to find a current recall but there will have to be one issued to ensure the safety of any american driving a Ford vehicle with this engine. After researching the internet I have found literally thousands of different people stating similar scenarios.