Got the o so famous leak above plug 4 the coil keeps getting wet and starts misfiring I thought it was from the heavy rain the other day so I just blowed it out with air. Today it started it again I figured I would pull the coil and look it had green antifreeze all over it. So now I have to find the leak I'm not sure if its the hose are the metal fitting in the intake. its not dripping so I can only think under pressure it's leaking so I got paper towels wrapped around some places I think it's leaking I will look back later and find which one is wet. Hopefully that will tell me where my leak is.

 

I had that same leak! Poored some Prestone stop leak in it, held if for a few months, came back so I poored another jug in, and hasnt leaked for probably 4 months now.

 

Damn I had a misfire in coil 4 after being In The snow for a few days using 4x4 and the heater a lot! I swapped coils with 4 to 1 when I can back the the SF Bay Area and its been good since, if u find that leak post it up here

 

On my truck, it was the heater hose, almost directly above the number 4 coil.Just enough to cause me trouble every few months. I added a second gear clamp to it, and crossed my fingers.That was in April, so we'll see.
Check that on your truck.

 

Was a very small pin hole in the heater core hose just before the clamp. I just cut some hose off and reclamped it and its fixed

 

I had the same leak and it was from the heater hoses. They have quick disconnect plastic clips into the heater core that can crack and break and then start leaking. It started on mine after I did a tune up and I most likely moved the heater hoses and they broke. It is a pretty easy fix to install new heater hoses. You pinch the clips together and they pull right off the heater core. I cut the clamp that holds the other end into the engine block and took them off. the new ones just push into the heater core (easy) with the plastic clip installed in the outer plastic shell. Somewhere in this blog there is a picture of what they look like and a detail description on where you push the clips to take them off. It is easy once you figure everything out but hard to see it when you are working on the truck.

Good luck

P.S. You can buy the new hoses on ebay for about $25 each.

 

http://www.f150online.com/forums/v8-...e-hoses-2.html

Here is a picture of the quick disconnect. When you press in on the clips of the piece on top, you can pull the hose off the heater core inlet and outlet. when all of those pieces are assembled, you just push the whole assembly on your outlet and inlet and it is installed and sealed. when the plastic is broken, it doesn't stay clamped and start leaking anti freeze.