When I had the turbo coolant fitting leak, there was coolant throughout the underside of the truck. But I was also losing coolant at a rapid rate. I've also had the upper radiator hose slowly start leaking into the valley and I didn't know about that issue.

 

I had some time today to finally check things out. The radiators look good, couldn't find anything bad on the hoses, but I did see that the fitting off the turbo appears to be leaking. The other thing I noticed is on the axle on the passenger side it's caked in something, almost like a bunch of oil dumped there and it's been collecting road grime ever since. I haven't found anything above that area for sure, right now I'm trying to follow where the coolant goes after it comes out of this fitting. Here is a picture of the fitting, it's hard to tell as it looks like a normal wet engine but the rest of the engine is bone dry and this is after not driving for a day.

 

Hey guys, just wanted to give an update in case anyone stumbles upon this thread later.

The coolant leak is fixed and it was confirmed to be that coolant fitting off the turbo leaking so I had my mechanic replace the whole line. It's only been done for a couple days so I don't want to get too hopeful here especially after what he said, but I have not heard the sound in the past couple days.

My mechanic (diesel mechanic at Ford for almost 20 years who still works there and opened his own shop) said that this is a normal sound. I wish I remembered exactly what he said but I do remember that the sound is something building vacuum, seems to me it was the waste gate but I'm not sure. Either way it's a normal sound that isn't hurting anything, they changed the design later on so the newer trucks don't make the noise but this is a common noise that doesn't cause any problem.

 

For the buzzing, air compressor noise, Ford started calling it normal several years ago. Mine didn't make that specific noise until 70,000 miles so either my truck was broken from the factory and it was supposed to make this noise (no...ha!) or it's not specifically normal in my opinion. Some trucks have the issue, some do not.

I didn't notice issues related to the wastegate noise for 30k miles but I've had so many problems in the past two years, I had it replaced anyways. The air compressor noise while running or after shutdown has not returned.