Join Date: Dec 2001
Location: Belleville, Illinois
Thanked 22 Times in 17 Posts
I've not taken this one apart, but it apparently has no spring, but instead just lifts a metal ball to close off the flow. When the vacuum is high enough to lift the ball, the valve closes, so it will only work in a vertical position.
In my particular case I suspect the ball has deposits that keep it from closing completely when it rises in a certain orientation. Many PCV valves I've seen have a spring that serves the function that gravity provides on this one. It's a pretty robust design, having lasted all this time, and I suspect it would be good for another hundred thousand miles if I just soaked it in something that would eat the deposits off it. In fact, I think I'll try some things to see what works, and then keep it as a spare.