GM Cadillac Deville_Fleetwood_ELD_Seville 1990-1998

PCV Valve


A Positive Crankcase Ventilation (PCV) system is used to consume crankcase vapors in the combustion process instead of venting them to the atmosphere. In gasoline engines, small amounts of the combustion gas leak past the piston rings into the crankcase. These crankcase blow-by gases contain undesirable hydrocarbon air pollutants. The PCV system is used to prevent these vapors from escaping into the atmosphere, while allowing proper ventilation of the crankcase to maintain good oil quality.

The PCV system should be checked at every oil change and serviced every 30,000 miles (48,000 km).

Never operate an engine without a PCV valve or a ventilation system, for it can become damaged.

removal & installation

  1. Locate the PCV valve; usually located either in the valve cover or in the intake manifold.
  3. Disconnect the crankcase ventilation tube from the positive crankcase ventilation valve.
  5. Remove the PCV valve from the PCV valve grommet.

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Fig. Pull the vacuum line off the top of the PCV valve

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Fig. A gentle twist and pull usually will remove the PCV valve from the valve cover

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Fig. A twist and a push will also install a new one

To install:

  1. Install the PCV valve into the grommet.
  3. Connect the ventilation tube to the PCV valve.