What causes excessive crankcase pressure?

Excessive crankcase pressure is often caused by a combination of factors, including worn piston rings, which allow combustion gases to escape into the crankcase, and a clogged or malfunctioning PCV (positive crankcase ventilation) system that fails to vent these gases properly. Other contributing factors can include excessive oil consumption, poor engine ventilation, and engine blow-by, where gases bypass the piston and enter the crankcase. This buildup of pressure can lead to oil leaks, seal failures, and reduced engine performance.