Positive Crankcase Ventilation (PCV) System: Overview

2010 Mercury Mariner Hybrid, AWDSECTION Overview
NOTE: Do not remove the PCV system from the engine. Removal of the PCV system adversely affects the fuel economy and engine ventilation and results in shorter engine life.

The PCV system cycles crankcase gases back through the induction system into the engine where they are burned. The PCV valve regulates the amount of ventilated air and blow-by gases to the intake manifold.

The hybrid vehicle uses a non-heated PCV system. PCV systems that comply with on board diagnostics (OBD) PCV monitoring requirements use a quarter-turn camlock thread design at one end to prevent accidental disconnection from the valve cover. For more information about the PCV monitor, refer to POSITIVE CRANKCASE VENTILATION (PCV) SYSTEM MONITORΒ .

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.