2007 Jeep Compass

Positive Crankcase Ventilation System

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PCV Valve



Operation

Specific to:

Jeep Compass 2007-2009

Jeep Patriot 2007-2009

The PCV system consists of the breather tube and the PCV valve. The breather tube connects the crankcase to a contained fresh air source such as the air cleaner. Air passes into this tube and into the engine after being filtered through a spark arrestor screen in order to prevent the possibility of an explosion within the engine in the case of a backfire.

During a normal compression stroke, a small amount of gasses in the combustion chamber escape past the piston. Approximately 70 percent of these blow-by gasses are unburned fuel (hydrocarbons) that can dilute and contaminate the engine oil, cause corrosion to critical parts, and contribute to sludge build up in the engine. At higher engine speeds, blow-by gasses increase crankcase pressure that can cause oil leakage from sealed engine surfaces.

The purpose of the Positive Crankcase Ventilation (PCV) system is to remove these harmful gasses from the crankcase before damage occurs and combine them with the engine-s normal incoming air/fuel charge.

Removal & Installation

Specific to:

Jeep Compass 2007-2009

Jeep Patriot 2007-2009

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Remove the engine cover.
  4.  
  5. Remove the hose from the PCV valve.
  6.  
  7. Unscrew the PCV valve.

    Click image to see an enlarged view

    Fig. Unscrew the PCV valve

  8.  

To install:

  1. Lubricate the O-ring on the valve.
  2.  
  3. Install the PCV valve and tighten the valve to 72 inch lbs. (8 Nm).
  4.  
  5. Install the hose to the PCV valve.
  6.  
  7. Install the engine cover.

    Click image to see an enlarged view

    Fig. Positive Crankcase Ventilation (PCV) valve location

  8.  

Testing

Specific to:

Jeep Compass 2007-2009

Jeep Patriot 2007-2009

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Start the engine and allow it to reach operating temperature.
  4.  
  5. Allow the engine idle to stabilize.
  6.  
  7. Pinch the hose or hold a finger over the PCV valve, if applicable. Typically, the engine RPM should drop around 50 RPM.
  8.  
  9. Check the PCV valve for excessive oil, carbon, or deposit build-up.
  10.  
  11. Check the hose or line for restriction/blockage.
  12.  
  13. Check for missing O-rings and for proper installation.
  14.  
  15. If the PCV valve is in question, replace the valve.
  16.  

 
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