Replacement of the PCV (Positive Crankcase Ventilation) valve on a 1966 Chevrolet Corvette 327ci V8 to maintain proper crankcase ventilation and prevent oil consumption or rough idle issues.

Warnings

Tools required

Parts

• PCV valve × 1 — Use OEM specification for 1966 327ci V8
• PCV valve grommet (if deteriorated) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and apply parking brake
2. Allow engine to cool to ambient temperature
3. Open hood and secure with prop rod
4. Locate PCV valve in driver's side valve cover (typically toward rear of valve cover)

Procedure

1. 1

   Disconnect PCV valve hose
   Locate the rubber hose connecting the PCV valve to the carburetor base or intake manifold. Gently twist and pull the hose off the PCV valve nipple. If the hose is stuck due to age, carefully use a flat blade screwdriver to pry between the hose and valve, taking care not to damage the valve cover grommet.
2. 2

   Remove PCV valve from valve cover
   Grasp the PCV valve body firmly and pull straight upward out of the rubber grommet in the valve cover. The valve should pull free with moderate force. If the grommet comes out with the valve, this is normal for aged grommets.
3. 3

   Inspect grommet condition
   Examine the rubber grommet in the valve cover (or on the old PCV valve if it pulled out). Check for cracks, hardening, or deterioration. If the grommet is damaged or hardened, use needle-nose pliers to remove it from the valve cover and install the new grommet by pressing it firmly into the valve cover opening until seated flush.
4. 4

   Test new PCV valve
   Before installation, shake the new PCV valve and listen for a rattling sound. The internal check valve plunger should move freely and produce an audible rattle, confirming it is not seized.
5. 5

   Install new PCV valve
   Push the new PCV valve straight down into the grommet in the valve cover until it seats firmly. The valve should be snug but not require excessive force. Ensure the nipple end of the valve faces upward and is accessible for hose connection.
6. 6

   Reconnect PCV hose
   Push the ventilation hose firmly onto the PCV valve nipple until it bottoms out. Ensure the hose connection is secure and will not pull off during engine operation. The hose should slide on approximately 0.5 to 0.75 inches onto the nipple.
7. 7

   Inspect ventilation system
   Trace the PCV hose to its connection point at the carburetor base or intake manifold and verify that connection is also secure. Check the breather/oil filler cap on the valve cover opposite the PCV valve to ensure it is clean and unobstructed. Wipe any oil residue from valve covers with a shop rag.

Reassembly

1. No disassembly required for this procedure

Verification

• Start engine and allow to idle. Listen for any vacuum leaks around the PCV valve area (hissing sound)
• With engine at idle, carefully disconnect the PCV hose from the valve. A strong vacuum should be felt at the valve opening and engine idle may become slightly rough
• Reconnect hose. Verify no oil leaks around valve cover grommet after 5 minutes of engine operation
• Check for smooth idle quality. Rough idle or high oil consumption were common symptoms of failed PCV valve

More procedures for this vehicle