Chrysler Front Wheel Drive Cars 4-CYL 1981-1995 Repair Information

Crankcase Ventilation (CCV) System



See Figures 1 and 2

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Fig. Fig. 1: A schematic of the Crankcase Ventilation (CCV) system utilized by the 2.5L Premier engine

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Fig. Fig. 2: The 2.5L Premier engine uses a vacuum orifice in the air inlet hose to draw crankcase vapors into the air charge entering the engine

The CCV system is only found on Premier models. The CCV system mixes crankcase vapors and fresh air from the air cleaner. This mixture is drawn into the intake manifold via a metered orifice.

The CCV system consists of a fitting in the intake manifold connected by a vacuum hose to the nipple on the oil vapor separator. The nipple has a metered orifice inside it. The oil separator is connected to the air cleaner.

The CCV system must be kept clean to maintain good performance and durability. Periodic service is required to remove combustion products from the valve, hoses, and the carburetor or intake manifold passages. The components should be inspected every 15,000 miles (24,000 km). If the vehicle is driven excessively on short trips with frequent idling, the CCV may require servicing more often.


  1. With the engine running, remove the CCV fitting.
    1. If the fitting is not plugged, a hissing noise will be heard as air passes through the valve. A strong vacuum should also be felt when a finger is placed over the fitting.
    3. Install the CCV fitting.
    5. Remove the fresh air hose from the air cleaner assembly and loosely hold a piece of paper over the open end of the hose. After allowing about one minute for the crankcase pressure to reduce, the paper should be sucked against the opening with a noticeable amount of force.

  3. Turn the engine OFF . Remove the metered orifice fitting, and check for a plugged condition. A clicking noise should be heard to indicate that the valve mechanism is free.
  5. If the crankcase ventilation system meets the tests in Steps 1 and 2 above, no further service is required. If not, the CCV fitting must be cleaned and the system checked again.
  7. If Step 1c still fails after the CCV fitting is cleaned, it will be necessary to replace the molded vacuum hose with a new one, and to clean the metered orifice port.
  9. Clean or replace the engine air cleaner filter element with a new one-for more details, refer to the air cleaner procedure located in Routine Maintenance .