"Dryer duct" tube coming from airbox?

There is a tube that comes from side of the airbox (air filter box) and goes someplace down toward the engine block (I haven't looked too hard as to where). I don't have a pic, but it reminds me of the ducting that comes from the back of a dryer or something.

Anyhow, the one on my XJ is all ripped and torn up so was wondering what it is, and what it's for.....

btw, I'm not talking about the tube to the TB...the tube in question here goes down below the intake manifold IIRC.....I suspect this is some kind of air heater for startup, but seems like it would be a detriment once the engine is warm if it's sending hot air into the intake...

btw, this is on a 1990 (Renix) XJ....

It is supposed to let the warm air from the exhaust manifold tunnel thru that "dryer tubing" into the airbox, to help bring the engine to operating temp in colder weather. Mine is ripped up too, you wont hurt anything without it being fixed, it will just take longer to heat up, depending on where you live...

Sounds like a hot air intake for when the engine is cold. It was common on carburetted vehicles (like the '74 Dodge in my avatar) to help warm the engine up and improve emissions, I believe. If yours is ripped up, it's not an emergency but you should probably replace it when you get the chance, the little hose is usually pretty cheap.

Usually it goes from the airbox to a bracket mounted on the header to draw air past the hot headers and pre-heat it. It had a vacuum actuated butterfly valve to switch between the heated air and the cool air once the engine warmed up.

Daedalus454 said:

Sounds like a hot air intake for when the engine is cold. It was common on carburetted vehicles (like the '74 Dodge in my avatar) to help warm the engine up and improve emissions, I believe. If yours is ripped up, it's not an emergency but you should probably replace it when you get the chance, the little hose is usually pretty cheap.

Usually it goes from the airbox to a bracket mounted on the header to draw air past the hot headers and pre-heat it. It had a vacuum actuated butterfly valve to switch between the heated air and the cool air once the engine warmed up.

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excellent, thanks. I'll have to see if the butterfly valve is still working too so as not to be pulling hot air when the engine is warmed up.

I have a brand new hose like you need. A buddy bought it and then trashed his rig. I am sure we could work something out if you need it.