PCV Valve

This procedure replaces the PCV valve on the 5.9L Cummins diesel engine to restore proper crankcase ventilation and prevent excessive pressure buildup.

Warnings

Tools required

Parts

• PCV valve × 1 — Use OEM Mopar specification
• PCV valve grommet × 1 — Use OEM specification if damaged

Preparation

1. Park vehicle on level ground and engage parking brake
2. Allow engine to cool completely
3. Open hood and secure with prop rod
4. Identify PCV valve location on driver side valve cover toward rear

Procedure

1. 1

   Remove engine cover if equipped
   If your model year has a plastic engine cover, remove the mounting fasteners and lift the cover straight up off the engine. Set aside in a clean area.
2. 2

   Disconnect PCV hose
   Locate the PCV valve on the valve cover. Disconnect the ventilation hose from the PCV valve by carefully pulling it straight off. Note the routing for reinstallation. Inspect the hose for cracks or deterioration and replace if necessary.
   ℹ️The hose may be stiff from age; do not twist excessively to avoid breaking the valve neck
3. 3

   Remove old PCV valve
   The 5.9L Cummins does not have a threaded PCV valve. If servicing the crankcase ventilation system, remove the applicable breather/CCV component per the specific engine variant (12-valve breather tube or 24-valve CCV filter), typically retained by clamps or fasteners rather than threads.
4. 4

   Inspect and clean valve cover opening
   Inspect the threaded opening in the valve cover for debris, oil sludge, or damage. Clean the threads with a shop towel. If the grommet or seal is damaged, replace it at this time. Check that the threads are clean and undamaged.
5. 5

   Install new PCV valve
   Install the correct crankcase ventilation component for the specific engine variant, following the OEM-specified fastener or clamp method. There is no threaded PCV valve or associated torque spec on the 5.9L Cummins diesel.
   Torque spec

   PCV Valve8 Nm (6 lb-ft)
6. 6

   Reconnect PCV hose
   Firmly press the ventilation hose onto the PCV valve connection until it is fully seated. Ensure the hose routing matches the original configuration and does not contact hot exhaust components or moving parts. The hose should have a secure fit without gaps.
7. 7

   Reinstall engine cover
   If equipped with an engine cover, position it back over the engine and secure all mounting fasteners. Ensure all connections made during this procedure are clear of the cover.

Reassembly

1. Verify all hose connections are secure and properly routed
2. Double-check that no tools or parts were left in the engine bay
3. Ensure engine cover (if equipped) is properly seated and secured

Verification

• Start the engine and allow it to idle for 2-3 minutes
• Listen for any unusual hissing or vacuum leaks around the PCV valve area
• Check for proper crankcase ventilation by removing the oil fill cap while engine idles - there should be slight vacuum, not pressure blowing out
• Inspect PCV valve and hose connections for any oil leaks
• Test drive vehicle and monitor for any check engine lights or rough idle conditions

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