PCV oddities

[Prairie Dog]

I've had an ongoing battle trying to stop the draft tube connection at the PCV box thingy from leaking. Several months ago I replaced the draft tube assy because the rubber boot at the PCV was deteriorated. However, I still get some seepage at that connection. The odd thing is, the bottom of the draft tube is perfectly clean. No oil has ever come out of it. .
I tried blowing backwards through it and it just pressurizes - Attaching a vacuum also reveals a clog. The draft tube is clear (I checked it) and I can stick my finger into the "box" and find no obstruction.
How can the PCV continue to leak oily crap at the DT connection (suggesting it's not clogged) but it won't go down the open draft tube??
Is there a check valve in the PCV?

 

[BGlidewell]

most PCV valves use a ball check valve. You shake them to see if they still rattle or are gummed up.

I've replaced my PCV valve on my cummins and it looked like it used a different type of "valving".

 

[rbattelle]

Are you sure you have a PCV valve? Was this an early 03 feature? My crank vent is just an air/oil separator - no valve.



Maybe retrofit an assembly like mine?



-Ryan

 

[Prairie Dog]

Ryan, I think that's what I have, just a box that tries to separate stuff.

I still can't understand why oil leaks out the rubber connections but not a drop comes out the bottom. I did extend the hose at the bottom about 6" but I can't see how that would do anything.

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[rbattelle]

Oh, yeah, we have the same system. It's not a "PCV" valve it's an air/oil separator. Inside that black box (you can take it apart) there's just a baffle. Air is removed out the top and oil (theoretically) drops down through a hole in the valve cover. Extremely simple. No filter, nothing to replace (unless it physically cracks).

What you might do is just take it off the valve cover and see if the o-ring that seals it in the valve cover has gone bad. Or maybe the housing is cracked on the bottom, or if a hose clamp was overtightened maybe the port is cracked.

Pull hard to remove it from the valve cover - the o-ring is tight.

-Ryan

 

[Prairie Dog]

Thanks Ryan, I keep it clean enough that I can see that it stays clean around the o-ring but keeps dripping from the connection at the large hose (draft tube). But it would be a good idea to check and make sure I haven't cracked the nipple.

Scotty