On an NA engine the breather is connected to the intake manifold, which on average, at a particular location always have less than atmospheric pressure. This pressure difference is what draws air into the manifold.

A federal 61x also has a butterfly that develops the manifold vacuum that draws in the EGR flow.

Once the breather is plugged, the blow by stream can rattle or float the cap, fill a trashbag held over the oil cap, or with the oil cap left on, pressurize the crankcase until the shutoff valve cuts the fuel.

In my view, this is just a way to rule out a used engine before you buy. If you already drive it, your oil consumption will tell you whether or not blow by is a problem, and starting whether or not compression is a problem. It doesn't really change the rebuild/replace solution set if you're stuck w/ the problem.

__________________
CC: NSA

All things are burning, know this and be released.

82 Benz 240 D, Kuan Yin
12 Ford Escape 4wd

You're four times

It's hard to

more likely to

concentrate on

have an accident

two things

when you're on

at the same time.

a cell phone.

www.kiva.org It's not like there's anything wrong with feeling good, is there?