3.0 pressurized crank case?

[jhelgesen]

Maybe someone here can answer this for me.

My 3.0 likes to spew great quantities of oil on the floor. Not all the time, just when it feels like it. The oil comes out of one of the oil tube to head joints. I figure I probably cut an oil return tube seal turing the rebuild, and have an expandable tube to replace it with.

I'm trying to discover why it come out in such quantity. It can sit for 2-3 weeks without a drop coming out, the one day, puke, there is a quart on the floor.

Here is my theory. They crankcase is a sealed system and rising temperatures in the shop cause pressure to build in the oil tank and crank case. Once pressure gets high enough, it finds the weakest point in the system (the bad o-ring) and relieves pressure, pushing oil out in great quantities.

Once I replace the tube, will it stop, or will it find the next weakest link? Do I have something hooked up wrong or missing in the system?

[Bill Verburg]

The crankcase and oil tank must breath. In the old days they were vented to atmosphere theses days the c/c is vented to the oil tank which is vented to the intake manifold. There is an operational pressure rise in the c/c but not too big(this is variable and depends on many factors), but as long as the breather to the oil tank and form the oil tank to the intake is unobstructed it should not influence the problem you describe.

The tubes are merely unpressurized oil returns to the c/c from the heads

[jhelgesen]

Guess maybe then I should make sure the breather tubes are clear then.