So I bought a new pancake valve, aka 034 valve, aka puck valve,aka pressure regulator valve, that plugs in the top of the air intake hose. The old one was pretty crappy inside (80K miles). Theres a spring inside so it seems like it should have some sort of movable plunger or something in it, but it's just wide open all the time. Even on the new one I don't see any moving part at all. WTF? Can anybody tell me how this things supposed to operate? Seems like it doesn't regulate anything, but it has a spring inside for something. What am I missing?

 

anyone?

 

It just regs the flow from the crankcase and head breathers with the intake. It really doesnt go bad, justs get clogged with crusty oil.

 

OK, thanks Cincy. So, apparently it's just a restrictor. I can't understand what the internal spring is for- looks like there's no moving part to it.

 

You might need to break the old valve apart to see it. There should be a round plastic piece on the top of the spring, you might just think its what the spring is mounted too but that side of the spring comes down when the vacuum on the turbo side of the valve is greater then the pressure on the crank case side of the valve.

 

Drives me crazy when I can't tell how something works! Getting **** in my old age I guess!
Theres a rubber diaphram at the top of the cavity that can get sucked down to the yop of the tube inside to close. My old one was pretty hard and stiff. The hole in the side of the tube is to make sure there is always an opening if the thing fails, I suppose. I think I'd rather have a catch can than suck this nasty crap into my intake.

Thanks for the info!

 

Catch can is always a good idea when it comes to the 1.8T, and the oil pressure problems it has. (dealer calls it sludge, i call it poor design)

 

Keeping it out of the intake track all together is the best thing to do. Even a catch can put in-line doesn't trap all of the oil vapor. Best thing is to use a vented catch can or a exhaust evacuation setup if you really want a vacuum source and still want to burn the vapor.