Question 197Motor Plants - Assistant Engineer

The correct answer is C) proportional to the lube oil viscosity. At temperatures below 70°F, the lube oil viscosity increases, which leads to higher frictional resistance when starting the diesel engine. This is because the increased viscosity of the lube oil makes it more resistant to flow, resulting in higher frictional forces within the engine components. Increasing the lube oil pressure (option A) may help overcome this, but the root cause is the higher viscosity. Reducing the compression ratio (option B) or heating the intake air (option D) do not directly address the issue of lube oil viscosity affecting the frictional resistance.