I found a hose disconnected under the hood today. It's the second pic on the car domain site with a circle around the end I found disconnected. I have a couple questions:

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1) What function does this hose do?
2) Was any harm done by this hose being disconnected? (possibly for a while)

Thanks

 

IIRC, that is the breather hose that sucks crankcase fumes back through the intake track (PCV) to be re-burned...lowering emissions. THe main concern would be sucking unfiltered air into your engine, but I doubt anything catastrophic will come of this. <<CROSS FINGERS>>

 

Really?! Wouldn't that just decrease performance to suck hot crankcase air back through the intake?

 

I couldn't find the nomenclature for it in the Nissan service manual. Just be advised that if that hose is disconnected, there will be a clear entry point for dirt and other contaminants to enter your engine. If you were to drive in a dusty evironment, you would cause uneccessary engine wear in short order. I'm thinking it's there as part of the emissions control system but I don't know what it's purpose is.

 

Yes, to some degree. Prolly not enough to notice, but there are K&N breathers that you can get to put on there and it will be fine. Not sure which is better, get the stagnent hot air out of the A/F mix and give it another pass or let it seep out on it's own.