What happens if the engine oil viscosity is too high?

[LaJake]

Engine oil with excessively high viscosity will: 1. Have slow oil flow during cold engine starts. Although oil pressure is high, the amount of oil passing through is limited, resulting in poor pumpability. This increases wear on engine components during the period from startup until oil reaches friction surfaces; 2. Require greater torque for crankshaft rotation during cold starts, leading to lower rotation speed and difficulty in ignition; 3. Circulate at slower speeds, reducing the number of passes through filters. This impairs the oil's ability to promptly remove metal wear particles, carbon deposits, dust and other contaminants from friction surfaces, diminishing its cleaning effectiveness; 4. Produce larger carbon residue particles with higher solidification points, which can easily clog oil passages.