If the oil pressure of a cold engine is higher than at normal operating temperatures, the engine's lubrication system is probably operating normally.

• A. False
• B. True
• C. Not enough data
• D. Cannot determine

Answer: (B)

Oil viscosity changes with temperature, so a cold engine has oil that’s thicker and offers more resistance to flow. The pump must push this thicker oil through bearings and galleries, which tends to raise the pressure. Once the engine warms up, the oil thins, flows more easily, and the system pressure settles to the normal hot-range. So seeing higher oil pressure when cold compared with normal operating temperature is expected and usually indicates the lubrication system is functioning correctly, assuming the hot pressure is within specification. If hot pressure were abnormally high or low, that would point to a problem, but the described pattern itself is normal.