OK, I'm embarrassed to admit it but I took the engine out of an F250, and then got really busy, and now that I'm back to it I don't remember this one detail.

There is a coolant tee on the intake plenum (a 90 degree bend that the throttle body bolts to). the rear-most tubing fitting goes to the back of the motor and y's off of the bypass tube under the intake. The fore-most tubing fitting goes to the front of the intake manifold to what I believe is the coolant temperature sensor. Both of these lines are small, I believe 5/16". The remaining middle fitting on the tee in the plenum is larger, about 3/8". I have an assembly of coolant lines that I am 99% sure attaches here, but this assembly has 2 other connections to make and I don't recall where they go! I don't even see any place for these to go!

Does anyone know? Have access to a diagram? Willing to take a pic of your truck? I hope to have this done on Wednesday and would really appreciate your help!

 

I looked more closely last night, and these would have to be vacuum lines. They do look more like vacuum tubing, but I made an assumption from the other 2 hoses that connect to the same tee.

I still don't see where this goes though. It smells of crankcase gases. I would think it was PCV tubing, but I'm fairly positive that its not because I have those on the motor already and am just about positive that they are correct.

I'm very thankful for any information or theories!