What would be considered a normal temperature increase between the inlet and outlet jacket cooling water of a medium or high-speed diesel engine operating at normal load?

Correct Answer: Option C — 10° to 20°F

Medium and high-speed marine diesel engines typically operate with a jacket cooling water temperature differential (delta-T) of 10°F to 20°F between the engine inlet and outlet to ensure adequate heat rejection without inducing excessive thermal stress on cylinder liners.