PCV Valve

This procedure explains the replacement of the crankcase breather filter on the 5.9L Cummins diesel engine, which serves the same function as a PCV valve in gasoline engines.

Warnings

Tools required

Parts

• Crankcase breather filter × 1 — Mopar 68031393AA or equivalent

Preparation

1. Park vehicle on level ground and engage parking brake
2. Allow engine to cool completely if recently operated
3. Open hood and secure with prop rod

Procedure

1. 1

   Locate crankcase breather
   The crankcase breather/ventilation assembly is mounted on the valve cover of the 5.9L Cummins. Verify the exact location, design, and hose routing against the factory service manual before proceeding, as the 2007 common-rail engine uses a specific crankcase ventilation configuration.
2. 2

   Disconnect breather hose
   Loosen the hose clamp securing the rubber breather hose to the breather housing using a flathead screwdriver. Slide the clamp back along the hose and carefully pull the hose off the breather housing nipple. Some oil residue may be present inside the hose.
3. 3

   Remove breather housing cap
   Remove the breather housing cap per the factory service manual. Verify whether the cap is bayonet/quarter-turn, threaded, or bolted before attempting removal to avoid damaging the housing.
4. 4

   Remove old breather filter
   Lift the old crankcase breather filter element straight out of the housing. The filter is a cylindrical foam or mesh element. Inspect the housing and valve cover opening for excessive oil accumulation or debris. Wipe clean with shop towels if necessary.
   ℹ️Some oil coating on the filter is normal. Excessive oil or a heavily saturated filter may indicate excessive blowby or extended service intervals.
5. 5

   Install new breather filter
   Insert the new crankcase breather filter element into the housing on the valve cover. Ensure the filter seats fully into the housing with no gaps or misalignment. The filter should fit snugly but should not require excessive force.
6. 6

   Reinstall breather housing cap
   Place the breather housing cap back onto the valve cover housing, aligning the tabs on the cap with the slots in the housing. Push down firmly and rotate clockwise approximately one-quarter turn until the cap locks into place.
7. 7

   Reconnect breather hose
   Push the rubber breather hose firmly onto the nipple of the breather housing until it is fully seated. Slide the hose clamp back into position over the connection point and tighten securely with a flathead screwdriver. Ensure the hose has no kinks or restrictions.

Reassembly

1. Verify breather housing cap is locked in place by attempting to lift it gently
2. Confirm breather hose is securely clamped with no air leaks
3. Inspect surrounding area to ensure no tools or shop towels were left in engine compartment

Verification

• Start the engine and allow it to idle for 2-3 minutes
• Listen for any air leaks around the breather housing and hose connection
• Verify no unusual whistling or hissing sounds from the crankcase ventilation system
• Check for proper engine idle quality with no rough running that might indicate an air leak

More procedures for this vehicle