Question 81Motor Plants - 1st Asst/Chief

The correct answer is C) lube oil cooler failure. If the lube oil cooler fails, it can allow lube oil to mix with the fresh water in the engine's cooling system, resulting in lube oil contaminating the cooling water. This is a common failure mode that can occur if the lube oil cooler develops a leak or cracks, allowing the two fluid systems to mix. The other options are incorrect because they do not directly result in lube oil entering the fresh water cooling system. A lube oil sump overflow, camshaft seizure, or lube oil pump failure would not typically cause this specific issue of lube oil contamination in the cooling system.