My practically new Ford EV-127A PCV valve had been leaking slightly while under full boost, which resulted in pressurizing the crankcase and blowing out the dipstick. I did not feel like putting in another stock PCV valve, and also my local Ford dealer does not stock them. I didn't want to wait for them to order one, so I decided I would make my own and be done with it.

I went to Lowe's and got a few simple parts from the plumbing section. Here's what I bought for my valve:

• 1/2" ID swing check valve with female threaded ends - $3.71
• 1/2" NPT hose barb to fit your stock lower PCV hose - $1.66 (I got a 1/2" x 1/2" [Watts A385], but the barb was too small - I shimmed it with a small piece of vacuum line.)
• 3/8" x 3/8" hose barb (Watts A-294) - $1.13
• 1/2" x 3/8" male to female bushing (Watts A828) - $0.93
• Teflon tape

There is not much to assembling and intalling the valve. Be sure that it is installed in the correct direction - air can be sucked from the crankcase, but not blown into the crankcase from the intake. When putting the valve in, I would think it is best to angle the valve so that the flapper is easily closed by gravity. Pretty easy to figure out, but see the second picture above.

This valve made a noticeable difference on my car. Boost used to climb to 20psi and then back down to 18psi at WOT, but now boost stays solid at 20psi. It appears that my old PCV valve was bleeding off around 2psi into the crankcase. Also, now I get a strong vacuum noise when I pull the dipstick or open the oil filler when the engine is idling. Never did that with the stock valve!

As always, if you have questions on this, feel free to email me.