HI, I am new on here and have not worked on vehicles in quite a while.
I have a 2002 f150 5.4 with 143000 miles. I noticed a stain under it and my coolant reservoir was empty.
When I filled the coolant reservoir it just started dripping off the passenger rear side of the engine with the engine not even running. I can not really see where the drip originates from as it is obscured from view.

Any ideas?

thanks

 

did you drive it after refilling the coolant?
If you drove it then it maybe a head gasket?

there maybe a frost plug that is bad back there? or there maybe a might be a coolant line back there as well

 

There is a heater pipe that connects to the back of the water pump underneath the intake manifold.

It uses an o-ring seal that is a common failure point.

Coolant leaks from the back of the pump and pools up on top of the engine under the intake, until it overflows off the back.

 

 

I think you have to remove the intake manifold to get to the line. You can reroute it. Do a search on this forum. this subject came up not long ago and video links were posted about replacing and rerouting that line as I remember.