Crankcase pressure explained

Question

Crankcase pressure is the pressure inside the crankcase of an engine, which houses the crankshaft and other internal components. It’s caused by blow-by gases, which are combustion gases that escape past the piston rings into the crankcase.

Key Factors:

• Normal Pressure: A healthy engine maintains a slight vacuum or very low pressure in the crankcase, thanks to the Positive Crankcase Ventilation (PCV) system, which removes these gases.
• Excessive Pressure: If the PCV system is clogged or malfunctioning, or if there’s excessive blow-by due to worn piston rings, crankcase pressure can build up. This can lead to:
  • Oil leaks
  • Seal damage
  • Reduced engine performance

Keeping the crankcase pressure balanced is vital for engine efficiency and to prevent damage to its components.

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