So I had been noticing a scent of antifreeze off and on lately. Checked it out today and found this.



99 F150, 5.4 with 190K miles. This is new coolant since I had my lower radiator hose burst on me back on New Years Eve. Coolant level is just below the low marking on the degas bottle.
What do you fellows think is leaking? Thermostat housing? Intake gasket? Head gasket?

 

from the pics I am going to say thermostat housing, or leak at the hose end.

 

Maybe a leak at the elbow or t stat?

 

Shine a light down into the valley - if there's puddled coolant under there it might be the O-ring on the pipe at the back of the water pump.

 

is it leaking at the top of the t stat housing or is it below by the intake gasket?

either way, its not too hard to change.

 

5.4 has plastic intake right? It could be the manifold itself. All though theres something in my head that maybe the 99 had an aluminum intake.

 

Yep, i have an aluminum intake. I'm researching this now to see what gaskets I need to replace.

 

Yeah, 1999 is aluminum still.

 

Hard to tell from the pic. He didn't take a pic of were it's leaking lol. Anyway, it's leaking at the stat housing. It's not gasketed itself, - uses the stat gasket instead.

What fails is either the housing itself, or of course the stat gasket. The housings pit and at times open up a hole in the casting itself. Those housings are cheap to replace, - so's the stat.

 

I will take a better picture soon when my weather improves and the engine isn't running.