I installed a new motor into my 97 s10 chevy 4x4 4.3 W. blazer, automatic, manual 4x4.
There used to be a black thick hose (size of a dime diameter or so) which would come somewhere from the bottom driverside and up, connected to a circle clip next to the fan black cover protector on driver's side, right next to the air filter black box. I'm guess it was a vacuum or over fill tube for the motor oil or simply air. It had a top button which was lose but didn't come off. Now that I installed a used motor, I don't remember if the tube went with the old motor or is it's underneath or possible it fail off and never put it back on, but I can't seem to find it. Can you help me, tell me the name of the tube and where it was supposed to be plugged underneath the motor, transmission, transfer case, radiator or what? Thank you.

 

AIR (air injection reaction) pump intake tube?

 

I think that is a front differential vent tube hes talking about.

 

Yep, you are correct. Too many threads at once I suppose. The AIR pump intake is on the passenger side and should have an OD about the size of a quarter. And now that I think about it, I'm not sure if the 96-97 trucks had the AIR pump...

 

thank guys. I haven't seen any pump in the front, just the oil filter. I have fixed the air condition a few times and have taking out the radiator..so I know that I haven't seen any type of pump near the front of the pumper. But I'll check again, look carefully in the front differential and / or for a pump to see If I can see an empty hole or plug where this tube used to be at? I'm not even sure if they sell this tube at auto zone or any auto part store. I'll keep you posted, and appreciate everyone's input.

 

OK, I found both tubes. The one on the front was laying down below the air filter box. The one next to the transmission dipstick tubing was laying to one side.