One problem related to engine knocking noise has been reported for the 1997 Ford E-350. The most recently reported issues are listed below.
The motor home engine operated fine while we were on an extended 1700 mile trip. The gauges registered normal. We checked the oil & antifreeze & they were at the normal levels. After we returned: at mileage 48526 we started the engine on may 6, 2004 the engine started with a large knocking noise & there was white smoke out the tailpipe. 2. Antifreeze had gotten into the oil so the rod bent & #1 cylinder was scored when the engine was started. 3. The head gaskets & head was normal - the whole engine had to be replaced!.