Mystery tube/mystery noise

[Staffsargent]

A friend asked me to post this-
A few days ago, I started up my M35A2 to make sure it was in good running
condition before a trip this weekend. About ten minutes after I shut it
off, I noticed a persistent noise. It sounded almost like raindrops
falling into a pot, one per second.
I popped the hood and listened from above, and couldn't locate it for
sure, but it sounded like it was coming from the air cleaner or turbocharger.
I slid underneath and figured out where the sound was coming from. There
is a tube, approximately 16 inches long and 1.5 inches in diameter, coming
straight down from the bottom of the turbo, exiting directly above the
axle.
I cupped my hand over the end of the tube, and it muffled the sound.
I had never noticed this tube before. So, my questions are:

(1) What is this tube? I would almost think it was an oil drain tube, but
it is so large in diameter.

(2) Any idea what that noise was? It persisted for over 15 minutes!

 

[Rolling_Eudaimonia]

That tube is the Crankcase Breathing Tube if you follow it all the way to the top you see it fits into your block. Mine is about 20-22inches long and extends below the axle... Why it made a noise for 15 minutes I do not know why.

 

[jasonjc]

Oil dripping back into the pan??

 

[bulldog_mack13]

did you give the turbo time to cool? and before driving?

its a slobber tube

 

[Barrman]

As pointed out above, it is the engine vent tube. For future reference, extend it below the axle so anything that vents or "slobbers" out will hit the ground first and not your front axle.

The noise could have been because the air compressor has weak piston rings. There should be a check valve going into the first air tank. However, if the tanks were full and the compressor had pressure built up in the lines. That air is going to want out. It could be slipping past the rings of the compressor, into the crank case through the comressor oil drain and then out the slobber tube on top of the engine. My Gasser 1952 M35 does this everytime I turn it off. I haven't heard it on the A2 however.