Jhave a 99f150 with a 4.6 coolant leaking from back of engine , thought it was the hard line under the intake replace it and as i was refilling the coolant i could hear it hitting the floor, could it be a freeze plug in back of the head ?any ideas would be a big help

 

Welcome to the forum!

Did you get it tracked down?

 

Best bet would to clean off the engine of and residue oil, grime, dirt, dust, coolant, ect. Sometimes a coolant leak will seep and run along a bracket, harness, engine part part, then actually drip down in a completely different part of the engine than you might think.

Sometimes a leak occurs when the engine is cold, and stops when the system gets hot and pressurized, and sometimes it occurs just the other way around. Regardless, it should be fixed.

With a clean engine and a bright trouble light, you should be able to pinpoint your actual leak very quickly. Good luck.

 

When you replaced the hard line under the intake, did you inspect the aluminum nipple the hard line connects to? The nipple I'm talking about, near the front of the engine under the intake , has two machined grooves in it that the o rings on the hard line fit into. The aluminum corodes over time from the inside out eating into those grooves. If that's it, then that nipple need to be replaced. It's a pressed in fit.

Something to check.

If that is the problem, remember to post back here so others can benefit.

 

Sorry for not replying sooner ,but thanks for the ideas ,what was leaking was the pipe on the back of the intake passenger side, this is pressed into the intake and it was cracked at the bottom, ford has the pipe but its a real pain to dig that pipe out of the intake . I tapped it out with a 3/8 pipe thread and and got a 6"nipple and barb fitting from the hardware store .my opion is this works much better than the factory pipe and if it ever leaks again i dont have to remove the intake to fix it. thanks again for the help

 

That is creative and it's a plus since you don't have to pull the intake.