I am tracing a rubber hose, which is cracked and leaking exhaust, from just above and behind the engine. It appears to be attached to a metal tube coming from the right side of the engine block. The hose feeds around the rear of the engine and then down the left side, down to a device located under the radiator cowling. It looks like a pump of some type, with electrical connections. Specifically, what is it? 2001 S-10, 2.2l 4 cyl. manual trans.

 

I just asked a friend of mine about this and he says its the air pump that you're talking about.

 

It is an air pump. It's the crankcase ventilation air pump, basically taking outside air and circulating it through the crankcase toget rid ofextra vapors.

 

Yeah that pump is what I just fixed on my truck. You probably should fix the hose of course because it runs the exhaust to the intake for reburning (secondary air injection A.I.R). You wouldnt want to pass out at the wheel. Can you smell exhaust in your interior?

If you want to know how the system works its supprisingly simple. From a glance at my alldata account I beleave its only open on start up for a short time to reduce emissions during warmup. I think the pump runs all the time and a vacum switch opens the check valve to alow exhaust into the engine. I was supprised how simple it was, This system is simply an emissions control so It doesnt effect operation drasticly aside from maybe mileage. I fixed mine because I like to keep my truck in perfect condition and I dont like check engine lights.