Volvo breather box tool

[JRL]

I borrowed this from Volvo today, I thought you guys would find it interesting.
A simple vacuum gauge (in bars, not lbs) with a tapered end that sticks into the dipstick tube.
This is actually a tool Volvo sells to dealers. There's a little tag with a Volvo P/N on it (wouldn't show up in the picture so no reason to post that shot).
Anyone can make this up, a simple vacuum gauge with a tapered end to make a snug fit over the dipstick
I tested it on my XC just now that has a fresh breather box, the gauge pegged all the way to the left, -.0,5

Better than the homemade one I have

[06ORXC]

Thanks for posting it.
What is a vacuum level that would indicate a breaking point between a clean and clogged system?

[JRL]

You need vacuum
I really say what is acceptable or not, perhaps half way on the gauge, I really don't know.
However, if it's clogged that gauge is not going to go negative, if anything it may go positive.... and you do not want that at all!
Right now, I have a car that's at 0, the gauge did not budge.
Why, I don't know yet, there is no puffing out the tube!

[sjonnie]

You need vacuum
I really say what is acceptable or not, perhaps half way on the gauge, I really don't know.
However, if it's clogged that gauge is not going to go negative, if anything it may go positive.... and you do not want that at all!
Right now, I have a car that's at 0, the gauge did not budge.
Why, I don't know yet, there is no puffing out the tube!

That's a great little tool. Note that the gauge is in kPA not bars so that's not a lot of vacuum, only 0.07psi. Not sure where you'd find a vacuum gauge that sensitive to make one yourself. I guess if the car is running and the gauge is 0, then there must be some flow through the PCV system. In order for vapors to be forced out of the dipstick tube you'd need a positive crankcase pressure.

[Scopeman]

Here is a simple manometer that I built. Prior to purchasing my 2005 XC (75 k miles, with "7500 mi oil changes") last November I did the "glove test", and it showed vacuum. Well that is not quite accurate. While it does show vacuum at idle and 2500 RPM no-load, when boost comes on the crankcase pressure rises above atmosphere, not acceptable. So, the cruise PCV circuit is plugged up. Parts will be ordered shortly after the tax man gets his hand out of my pants.
I used a replacement oil cap from NAPA, an unused 10ml syringe, and inserted a plastic bead with the hole filled with epoxy. The bead will stay in the "good" end, against the hose end until boost occurs, at which point the bead will go to the other end.
I stole the idea here: http://www.youtube.com/watch?v=d0SoAjX2xwM It requires two people, one to watch the manometer, and the other to press the gas and brake, in gear. Go easy, and make it fast, not good for the trans..

[DakotaMike]

If you have a positive pressure situation with your engine and doing a PCV replacement is not possible immediately would it be possible to use some form of vented oil cap to save the pressure causing other problems until the PCV can be fixed?

[JRL]

I figured that out just now
I was told this is too sensitive and a regular vacuum gauge won't work.

If you have a positive pressure situation with your engine and doing a PCV replacement is not possible immediately would it be possible to use some form of vented oil cap to save the pressure causing other problems until the PCV can be fixed?

Not the best of ideas

[Scopeman]

As I understand the PCV system, the idle circuit is a hose connected to a port on the intake mainifold, then to the PTC nipple on the intake hose near the turbo. That would apply manifold vacuum to the PCV system. At cruise, the much larger air flow volume through the turbo intake hose passing over the PTC nipple causes PCV flow in the larger tube connected to the oil separator box, drawing the blowby gasses out. So a combination of partial blockages in all of these components contribute to inadequate PCV flow, especially under boost conditions.

[Willy]

Note that the gauge is in kPA not bars so that's not a lot of vacuum, only 0.07psi. Not sure where you'd find a vacuum gauge that sensitive to make one yourself.

I think the main thing is that there is no pressure, I don't think much vacuum is present even in a new engine.
It must be possible to make a gauge yourself using a U-tube setup of some kind, see: http://www.instrumentationtoday.com/page/3/
For a more sensitive setup see the inclined U-tube type.
But JRL's tool is certainly handier
Willy

[BillAileo]

I think Willy is on target. Wouldn't it be possible to simply set up some sort of coat hanger wire frame to create a U-tube of plastic tubing; put a small amount of engine oil in it and attach a tapered fitting to one end, possibly using fittings from a MityVac?