Secondary Air Intake Hose
 

First off let me say that this is an 89' S10 4.3L. Now i asked one of the guys at Advanced Auto and he told me that this secondary intake hose ( pic #1) was used at startup to heat up the air until the engine has warmed up. now my question to you all is: when i yank all of this out to put in my K&N xtream air airflow setup, this is obviously going to leave an open hole in the engine that i believe needs to be covered.(pic #2) does anyone have any experience with this? if so how did you cap this off?

That hose just connects to the heat shield around the exhaust manifolds, not to any ports from the engine itself. It pulls outside air over the exhaust manifold to heat it up. With it disconnected, there will be a normal flow of air through it due to hot air rising, but it will not adversely affect the operation of the engine.

so if water or mud and crap get in there it wont cause any harm?

Nope. There really isn't anything keeping mud/crap out from the underside anyway.

That hose is connected to a heat shield (for lack of better words) that just sits above the exhaust manifold. It does not connect to the engine, manifold, valve cover, or anything like that. You will be safe. Most older engines are already missing this hose or the hose is ripped and torn to a non-functioning point anyway. You just don't want to leave the open hole in the bottom of the air cleaner cover because trash, dust, and moisture can be sucked in. But if you are going to a C.A.I. system, this should not be an issue.

That hole in the bottom of the intake pipe is before the filter anyway. If he is replacing the filter, he won't be keeping the stock filter housing which connects to the heat riser pipe so that is a moot point in this case.

Good for someone that is just doing a drop in filter though. If you were doing that, you would want to gut out the valve in the pipe, plug the hole, and disconnect/plug any vacuum lines.

thanks for the help guys. i just wanted to make sure that it didnt need to be plugged to keep junk out.