I have a '99 with a 5.4 it has a small antifreeze leak at the front of motor to the center of the thermostat. The port it is leaking at "looks" like a 3/8 vacuum hose going to the throttle body. It connects to the throttle body on the left side. I'm not sure if I'm seeing it wrong or what. I've can't figure a reason for water to be running up there or have never seen heater hose that small. Any help would be appreciated still not to familiar with these high tech machines.

 

I can't recall your specific application from memory; however, what you see is most likely correct. Engine coolant is used to heat the throttle body and in come cases the PCV valve.

It may be the hose or just the clamp. I'd replace all three (hose and two clamps).

 

On my '99 Navigator, there is a small heater hose coming from around where the thermostat is, up to a fitting pressed into the side of the intake manifold on the passenger side, and then a return line back to the thermostat. (There is a vacuum line that connects to this fitting).
This fitting had developed a leak. You can get just the replacement fitting from Ford, (not the entire manifold with fitting like some dealers will tell you).
You just pull out the old one and press in the new one.

 

Typed too fast.

It's not a vacuum line plugged into it, it's a PCV line.