I have a1997 F150 4.6 with a coolant leak( I think it is coolant) There is coolant in the valley between the heads under the aluminum intake manifold. It runs down onto the starter and then to the drive and is pretty heavy. Would this be a gasket, cracked manifold ,or maybe the heater pipe that runs under there. Have read Several post on 5.4 leaks with plastic manifolds, but mine is metal so I am leaning more towards gasket or pipe. The 4.6 does have the same pipe as the 5.4 doesn’t it? Looking for thought before I tear it apart. Thank for any info.

 

get yourself some coolant UV dye and a UV light/glasses. That will pinpoint the source of the leak

 

Could be a couple things right there. My money is on one of the fittings for the heater core.

As far as that pipe under the intake is concerned, they are not too bad in price brand new... usually around 40 dollars. Personally, I'll throw down 40 all day to not have to remove the intake again because I bought a used pipe.

 

I agree. About the only weal link is the rubber hose that's crimped onto the line that goes bad over time.
Try to get a Motorcraft replacement part if you can. Rock Auto is where I went to.