Customer FAQ

That usually depends on the mileage. We've received reports of the check valve still being visible, but once the tip was broken off and the flap was shaken out of the intake manifold, it is revealed that the entire flap (the portion that should function as a non-return valve) was completely disintegrated and served no purpose. If the intake manifold has over 40,000 miles, the rate of failure increases exponentially with mileage, so while you may not need the kit now, it may be a good idea to install it preventively to avoid the snowball of issues and expenses that come when it fails unexpectedly.

Yes! This would be considered a preventive maintenance, or manifold upgrade install. There are two ways to do this.

1. With the manifold still in the car, find a flathead screwdriver, rest it against the nipple protruding in the manifold, and give it a whack with the palm of your hand to break it off. The nipple would remain inside the PCV chamber of the intake manifold and would have nowhere to go. The flap on the back side would eventually be consumed by the engine through one of the cylinders and burned through the exhaust. This is the same manner in which the check valve fails on its own, and no problems have been reported from this approach.

2. You can remove the intake manifold, break the tip off in the same fashion, and shake the flap out afterward. If you have any concerns about the check valve being ingested by the engine and causing any issues, this would be the better option. Doing this also gives you a better opportunity to clean the intake manifold thoroughly and check the PCV port on the cylinder head to make sure it's free of deposits.

Yes, but the manifold will have to be out of the car for the installation. The aftermarket intake manifolds have a check valve wall recessed further back in the intake manifold, making it impossible to plug the hole from the top of the port opening as with the OEM intake manifold.

If you plan on installing the kis kit on a Dorman manifold, please leave us a note in the Special Instructions box in your cart, and we will include the screw and washer needed to plug the check valve port.

If you already have the kit and need the hardware, you'll need a #10 x 3/4" self-drilling sheet metal screw, and a #10 x 7/16" nylon washer.

Yes, the valve cover is a separate component. The PCV Fix kit addresses the failure of the intake manifold check valve, which causes premature failure of the valve cover, but the valve cover itself houses a vacuum regulator diaphragm. If that has failed, the valve cover will also need to be replaced. Be sure to only use OEM valve covers.

Eventually, yes. The valve cover house a vacuum regulator diaphragm, which is made of a silicone-type rubber that deteriorates and eventually tears. Failure of the intake manifold check valve causes premature failure of the valve cover. With the kit installed, most customers report getting 60,000-120,000 miles (96,500-193,000 km) or more between valve cover replacements.

The telltale signs of a check valve needing replacement are onset of external leaks, increased oil consumption, and loss of fuel economy or power. If any of these symptoms exist, you should check and test the check valve to ensure it's still functioning properly.

For the V1 and V2.1 kits, we recommend checking and cleaning the check valve every 75,000 miles.

For the V3.4 kit, we recommend replacing the check valve every 30,000 miles in colder climates and 50,000 miles in warmer climates.