Bypass cannister

I believe that this cannister is a crankcase vapor condensation device. Oil evaporating from the hot engine crankcase will collect in the cannister, and negative pressure from intake manifold recycles the vapors back into the combustion chamber. Vapor not pulled into the intake manifold condenses and drips back down the hose to the crankcase. Rust is normal in any engine part where water vapor and oil vapor meet. Take note of your oil filler cap - also likely to have rust. Not an issue. Won't hurt the engine.

Jim S.

 

Jim, yes, that's what this thing is.

Driving a car short distances would leave water coating the inside when the car was shut down, predisposing to rust forming there.

The liquid water presumably would have run down the smaller diameter hose to the crankcase oil, where water is also not a good thing to have.

Jim O