Hi Fellas,

I'm curious when the OEM Motorcraft PCVs switched from all metal construction to plastic ABS?

It has been a while since I bought a Ford Motorcraft OEM PCV. I normally purchased Napa or Lordco brand in the past and they have always been all metal construction, but just today I picked up a Motorcraft and it of course is a plastic unit.

A side note: (more curiosity)
I noticed that the new Motorcraft plastic PCV actually does not work the same as the old all metal units for my truck. The air restriction in the Motorcraft plastic unit when closed is almost none existant compaired to the old unit which restricts the air flow to the point where only a small of air gets by the valve when closed. I thought the PCV was supposed to heavily restrict the air flow into the engine at idle (low vacuum)? The Motorcraft pretty much allows the air to flow unrestricted even at idle.

Any legitimate reason why the Motorcraft PCV would allow so much more unrestricted air flow at idle?

Rick...

 

That's weird, I think my stock '01 PCV is plastic with the metal bottom. Now you have me curious

The only thing the wide-open PCV will do is allow more air into the intake past the throttle body. Since the PCV breather is connected to the intake tube after the MAF, this is metered air and the PCM will see it.

It just means the PCM will close down the IAC more to keep the idle where it's supposed to be and probably won't effect anything. Unless, of course, you have a lot of blowby.

 

Art,

I might guess your PCV has a plasic elbow with it? If you remove the elbow it should be the all metal standard PCV as we know them.

The idle on my truck actually seems to be slightly lower with the new PCV. Using my ScanGauge as reference,,, before the new PCV it would idle at approx: 860-900 (give or take) and with the new unit it's at approx: 790-830 (give or take) and it seems to get down to idle a little bit quicker now. It was only a quick test drive after I installed the new PCV last night and I can't confirm this 100% yet because I'm waiting for delivery of a 10 pack of new Motorcraft coils (I suspect a bad coil might be effecting the idle a little bit at this point). I'm hoping the coils will show up early next week then I can maybe confirm the at idle RPM.

The new PCV does restrict the airflow a little bit. If I had to quesstimate,,, I would say the old unit when closed restricted the air flow by approx: 95%.
The new plastic unit (EV-238= "233 PCV" & grommet / part# F75Z-6A666-BA for '99 through '03 or '04) restricts the air flow by approx: 20%.
This seems like a very big difference to me, but it seems to work.

I just hope the new PCV does not effect the blower operation in a negative way. I can't see how, but I'll find out when the new coils are installed.

Side note:
I'm wondering if the new PCV's more unrestricted air flow might help with the humm/tuba issue with some 5.4 and 6.8 owners? Since it effects the IAC it just might help alleviate that irritating sound.

Rick...