I bought my girlfriend a 2001 Chevy Blazer 4WD and I've been slowly going through it and fixing all the crap that's wrong with it over the past several months. This weekend I started tearing into it to do a complete cooling system overhaul (replace radiator, hoses, heater core, water pump, etc.) and a intake manifold gasket swap. As I'm tearing things down I notice this heater style rubber hose that looks out of place so I pull on it to start tracing it and the one end isn't connected to anything! The other is connected to the pump looking device which also has a separate heater type hose connected to it that goes to a T-junction under the harmonic balancer and then there are rubber heater type hoses that go from that T-junction on each side up to metal pipes attached to the front end of each exhaust manifold. What the hell is this thing and why have I not seen it anywhere in the photos of my Haynes manual or online?

 

Its 2010 pictures would be nice. However it sounds like its the air pump that pumps air into the exhaust to help with emissions.

 

Yep, part of the air pump system.

 

I think the dealer name for that part is a "widget mcdoodle thingy".

 

Thanks for all the replies guys. I feel retarded but I've never seen that type of component before, threw me for a loop! And for the record I had taken pictures to post, but I guess in my absent minded hurry to get back to wrenching I neglected to post them up. My apologies!