mysterious splat of oil out of filler tube

[libbydiesel]

If you pull the main line off the vacuum pump or if there is a currently plugged tee nipple, you can then pull a vacuum on it using a mityvac or similar.  It takes a LOT of pumping, but it should pull a solid vacuum and not bleed off unless you have a leak. 

So you have oil dripping out of your muffler?

I think off of rather than out of.  The muffler is right behind the filler tube.  When oil pukes out the tube, it lands on the muffler. 

The hockey puck is a 'pressure control valve'.  It has a diaphragm within it that has a spring that keeps the valve open.  Crankcase pressure is on one side of the diaphragm and intake pressure is on the other.  The valve closes when intake vacuum pulls the diaphragm closed against the spring pressure.  The reason for that behavior is as a safeguard against runaway.  If that valve were not in place, if there is any intake restriction, then the engine can suck hard on the crank vent and runaway off the oil it pulls through.  Unfortunately, if the valve closes, the crankcase pressure will build and take the path of least resistance, in this case puking oil out the dipstick.  The puck could certainly be at fault.  An intake restriction could as well.  I believe excessive crankcase pressure could also cause the valve to close and cause the puking of oil even if the intake is not restricted and the hockey puck is working correctly.   

[libbydiesel]

I also wanted to mention that the quietest TD vanagon installation I've done used a custom filter box and intake to the box that significantly mitigated intake noise.  I used a 2.5" spiral flow muffler.  You could certainly hear it under power, but was very reasonable.  It was difficult/impossible to hear the engine idling (over the road/tire noise) when slowing to a stop, until you actually stopped.

[zuhandenheit]

If you pull the main line off the vacuum pump or if there is a currently plugged tee nipple, you can then pull a vacuum on it using a mityvac or similar.  It takes a LOT of pumping, but it should pull a solid vacuum and not bleed off unless you have a leak. 

I wish I had something I could use for this. Maybe I could t-in my boost gauge . . .

So you have oil dripping out of your muffler?

I think off of rather than out of.  The muffler is right behind the filler tube.  When oil pukes out the tube, it lands on the muffler. 

The hockey puck is a 'pressure control valve'.  It has a diaphragm within it that has a spring that keeps the valve open.  Crankcase pressure is on one side of the diaphragm and intake pressure is on the other.  The valve closes when intake vacuum pulls the diaphragm closed against the spring pressure.  The reason for that behavior is as a safeguard against runaway.  If that valve were not in place, if there is any intake restriction, then the engine can suck hard on the crank vent and runaway off the oil it pulls through.  Unfortunately, if the valve closes, the crankcase pressure will build and take the path of least resistance, in this case puking oil out the dipstick.  The puck could certainly be at fault.  An intake restriction could as well.  I believe excessive crankcase pressure could also cause the valve to close and cause the puking of oil even if the intake is not restricted and the hockey puck is working correctly.   

Given that my vent is routed through a catch can to the atmosphere, most of this would not apply, correct?

But I assume that if the hockey puck were getting stuck closed, that could cause this. It's strange to me that it's so intermittent and has happened at apparently random times -- twice at idle and then once while driving.

[zuhandenheit]

I am *very* interested in your quiet intake/exhaust! I really want to make this motor more quiet.

The exhaust helped. I just finished it today. I only had flux-core wire and hoped that it would be okay for the relatively heavy-gauge pipes. I hate it so much, though, and made a big mess. I'm not good at welding anyway, and have almost no experience with flux-core wire. I won't weld again until I get some gas.

For now, the muffler is just clamped, and maybe this is good after all -- I'll try it out for a bit, and then possibly try to get something quieter. It's kind of a hacked together setup . . .



It was an awful lot easier to attach to the frame than to the engine. I've got a flex section and rubber straps, so hopefully it will be okay. There's no noticeable extra vibration.

At this point, I think the worst of the noise is coming from my intake. I have a Donaldson filter under the rear pillar, which I'm planning to move next to the transmission when I install my intercooler. I was thinking about attaching something to the inlet of the filter and making some kind of box to quiet it.

[zuhandenheit]

This problem is still not solved.

It happens only very rarely, on long highway runs (twice in the last six months, both times when I was driving over 65 for more than an hour).

There are some things that have been suggested here that I still need to check -- my apologies for coming back without having done full diagnostics. I've been busy with other stuff and the problem didn't recur, so I put it out of mind. However, I'd really like to soon take a long trip, and this is the one thing stopping me.

I was planning to replace my air filter (though it's not too old) to rule out the possibility of an intake restriction. However, I realized that because my crankcase is vented to the atmosphere, there wouldn't be any way for the valve in the puck to be closing due to intake restrictions. The vent is attached just to the crank and the valve cover, and then there's a tube which was going to a catch can -- but I wanted to rule out the possibility of a restriction in the can, and so it currently is just open.

So I figure I should next check for a vacuum leak.

Maybe I'll try replacing the oil separator -- I have a second somewhere.

And finally I guess I should do a compression test.

Anything else? This problem really sucks, as it's intermittent and yet serious enough that I won't take the van on any trips until it's resolved.

Thanks!