The PCV valve is an often overlooked maintenance item that can lead to some pretty severe engine related issues if left unchecked. Over time, the PCV valve can become contaminated with oil and moisture that will cause the valve to stick in the opened or closed position, thus limiting its function. A traditional PCV valve will typically last 75,000 miles, but with it being such an inexpensive part, many individuals opt to replace them at 30,000 mile intervals for piece of mind.

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This article applies to the Ford F-150 (1997-2008).

The Positive Crankcase Ventilation valve, also referred to as a PCV valve, was one of the first emissions related components to be fitted on vehicles. In short, the PCV system routes vapors from the pressurized crankcase back into the intake manifold, where they are eventually burned during the normal process of combustion. A normal occurrence during the combustion process is to have small amounts of fuel and other byproducts make their way into the crankcase by seeping past the piston rings. To prevent these contaminants from condensing in the crankcase and causing sludge, fuel contaminating the engine oil, or excessive crankcase pressures, a PCV valve is in place to allow the vacuum of the engine to siphon vapors from the crankcase and reduce pressure and the formation of moisture.

A PCV valve can fail in a variety of ways and cause a number of issues, including excessive oil consumption, engine misfires, excessive oil leaks from high crankcase pressure, engine hesitation and loss of throttle response, as well as sludge contamination. While it performs an important task, a faulty PCV valve is a component that can be quickly and easily replaced without the use of any special tools. This article will outline the PCV valve replacement procedure for the 1997 to 2008 Ford F-150 models.


Step 1 – Locate and remove PCV valve

Despite the various changes between each model year, the PCV valve is typically located in the passenger side valve cover.

As mentioned, many PCV valves are located on the passenger side valve cover; however, some later 5.4L Triton V8"s will have them installed in the driver side valve cover/intake manifold. These later engines do not use an actual PCV valve per se, but instead utilize a hose that incorporates a heated valve that is supposed to have an extended service life compared to a traditional valve.

Figure 1. Passenger side valve cover with PCV valve.

Remove the hose from the end of the PCV valve. Note that some engines will have a hose clamp securing the hose to the end of the PCV valve, whereas others will not and can be simply slid off of the end of the valve. Also, later year models using a heated valve will require the electrical harness to be disconnected prior to valve removal.

Figure 2. Removing breather hose from PCV valve.

Depending on the engine, some PCV valves can simply be slid out of their rubber grommet in the valve cover, while others may be held down by two small bolts. In some cases, a wrench or pliers may be required for removal, as some valves screw completely into the valve cover or lock into the valve cover via a 1/4 turn quick connect.

Figure 3. Removing 1/4 turn PCV valve with adjustable wrench.
Pro Tip

When replacing the PCV valve, it is highly recommended that you inspect any hoses and rubber grommets for splits, cracks, or holes and replace if necessary.

Step 2 – Install new PCV valve

Before attempting to install the new PCV valve, compare it with the old unit to ensure they are the same. With variations in design, it is common for individuals to end up with the wrong valve.

Install the new PCV valve into the valve cover or intake manifold (depending on engine model). For valves using a slip fit into the grommet, a light coating of oil or silicone spray can aid in installation. If a 1/4 turn design is used, slide the valve into the valve cover and turn it clockwise until it locks securely in place. Similarly, if you have a threaded valve or a valve that utilizes hold-down bolts, simply tighten the valve or bolts until they bottom out and the valve is secure.

Figure 4. New PCV valve ready for installation.

Attach the hose to the PCV valve. Install any hose clamps and the electrical plug if applicable.

Figure 5. New PCV valve installed (1999 5.4L engine shown).

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Pro Tip

A traditional PCV valve can typically be tested by shaking it. If the check ball inside is loose and rattles freely, the valve is considered to be in good working order.