Oil Separator/PCV

Replace the PCV valve and associated hoses on the 1972 Ford F-100 302ci V8 to restore proper crankcase ventilation and prevent oil contamination of the intake system.

Warnings

Tools required

Parts

• PCV valve × 1 — Use OEM specification for 1972 Ford 302
• PCV valve grommet × 1 — Use OEM specification
• PCV hose (valve cover to intake manifold) × 1 — 5/8 inch ID, approximately 18 inches
• Breather hose (valve cover to air cleaner) × 1 — 3/4 inch ID, approximately 12 inches
• Hose clamps × 4 — Worm gear type, appropriate sizes for 5/8 and 3/4 inch hoses

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.
4. Remove air cleaner assembly by loosening wing nut and disconnecting breather hose to access PCV system.

Procedure

1. 1

   Locate PCV valve and system components
   Identify the PCV valve, which is located in a rubber grommet on the passenger's side valve cover near the rear. Trace the hose from the PCV valve to its vacuum source at the carburetor base or intake manifold port. Locate the breather assembly on the driver's side valve cover and its connection to the air cleaner base. Trace the hose from the PCV valve to its vacuum source at the carburetor base or intake manifold port. Locate the breather assembly on the passenger side valve cover and its connection to the air cleaner base.
2. 2

   Disconnect PCV valve hose at intake manifold
   Using needle-nose pliers, squeeze and slide the hose clamp away from the intake manifold fitting. Twist and pull the hose off the intake manifold nipple. If the hose is stuck, use a hose pick to carefully separate it from the fitting without damaging the intake manifold port.
3. 3

   Remove PCV valve from valve cover
   Grasp the PCV valve firmly and twist while pulling upward to remove it from the rubber grommet in the valve cover. The valve should come out with moderate force. If the hose is still attached to the valve, slide the clamp back and remove the hose from the valve end.
4. 4

   Remove PCV grommet from valve cover
   Using a flathead screwdriver or needle-nose pliers, carefully pry or pull the rubber grommet from the valve cover opening. Inspect the grommet for cracks, hardening, or deterioration. Replace if it shows any cracking, hardening, or deterioration.
5. 5

   Disconnect breather hose from air cleaner base
   Locate the breather hose connection at the air cleaner base (if not already removed with air cleaner). Loosen the hose clamp and remove the hose from the air cleaner nipple. Trace this hose back to the driver's side valve cover breather assembly.
6. 6

   Remove breather assembly from valve cover
   The breather cap/filter assembly on the driver's side valve cover typically pulls straight up from its grommet. Twist and pull firmly to remove. Remove the associated grommet if it is damaged or hardened.
7. 7

   Inspect and clean valve cover ports
   Examine both valve cover openings for oil sludge, carbon deposits, or debris. Use a wire brush and parts cleaner to clean the grommet seating areas and ensure smooth surfaces for the new grommets. Wipe away any loose debris with shop rags to prevent it from falling into the valve cover.
8. 8

   Inspect intake manifold PCV port
   Check the intake manifold PCV nipple for carbon buildup or blockage. If heavily clogged, carefully clean with parts cleaner and a small wire brush. Ensure the port is open and clear for proper vacuum signal to the new PCV valve.
9. 9

   Install new PCV grommet in valve cover
   Lightly lubricate the outer surface of the new PCV grommet with clean engine oil. Press the grommet firmly into the valve cover opening on the passenger's side, ensuring it seats completely and sits flush with the valve cover surface.
10. 10

    Install new PCV valve
    Insert the new PCV valve into the grommet with a firm twisting motion until it seats securely. The valve should be snug but not require excessive force. Ensure the valve sits at the correct angle for hose routing to the intake manifold.
11. 11

    Connect new PCV hose
    Route the new PCV hose from the valve on the passenger's side valve cover to the intake manifold nipple. Ensure the hose has no kinks or sharp bends. Connect one end to the PCV valve and the other to the intake manifold fitting. Slide hose clamps over both connections and position them 1/2 inch from the hose ends, then tighten securely.
12. 12

    Reinstall breather assembly
    If the breather grommet was removed, install the new grommet in the driver's side valve cover opening using the same method as the PCV grommet. Press the breather cap/filter assembly firmly into the grommet until seated.
13. 13

    Connect breather hose to air cleaner
    Route the new breather hose from the driver's side valve cover breather assembly to the air cleaner base nipple. Ensure proper length without stretching or excess slack. Install hose clamps at both ends and tighten securely.
14. 14

    Reinstall air cleaner assembly
    Position the air cleaner assembly back onto the carburetor and reconnect the breather hose if not already connected. Secure the air cleaner with the wing nut, tightening hand-tight only.

Reassembly

1. Double-check all hose connections are secure and clamps are properly tightened.
2. Verify no tools or rags were left in the engine compartment.
3. Ensure all hoses are routed away from hot exhaust manifolds and moving components.

Verification

• Start the engine and allow it to reach idle. Listen for any vacuum leaks (hissing sounds) around PCV connections.
• With engine at idle, carefully remove the oil filler cap. You should feel slight vacuum or no pressure (cap should not blow off). Replace cap.
• Remove the PCV valve from the grommet while engine is idling. You should hear a hissing sound and feel strong vacuum at the valve inlet. A rattling sound when shaking the valve indicates it is functioning.
• Check for oil leaks around valve cover grommets after 5 minutes of operation.
• Rev engine briefly to 2000 RPM and verify no oil mist or excessive blowby is visible from the breather assembly.

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