What is a crankcase breather line?

[jspeed87]

I can't seem to find it in the PHAK or AFH. I know if that line freezes shut you can have an engine failure. Where do I look for such line/hose when doing a preflight or a picture of it would be nice.

 

[KDoersom]

The crankcase breather is a tube that comes out of either the top or top back of the engine depending on the model. On the smaller continentals it is in the top front of the case. It lets the crankcase breath so pressure doesn't build. Is also will vent excess oil out the tube and deposit it all over the belly. The tune ends outside in the cowling and is probably anywhere from a 1/2 inch to an inch in diameter.

 

[jspeed87]

I'll look for it/ask mu CFI next time. I'm surprised there is no picture of it in the text books.

 

[gotWXdagain]

If moisture gets into the engine crank case, then when the engine is turning it will vaporize due to the heat. This causes a pressure buildup, so the breather is there to vent that pressure overboard.

...or so I've heard...