smithka

I've got an '04 Super Crew with the 5.4L with 120K miles on it. Just recently it has started to make a noise that sounds like air blowing with a slight rattle. It only seems to do it when it is under load (accelerating up hill or onto the highway) and when I back off the gas, it stops. I'm not having any trouble with overheating or rough idle. Could it be the fan clutch?

Any help is greatly appreciated! I'm not having any performance issues now, but I'd like to get it solved before I do...

tcp2

Check the seals on your airbox.

https://www.f150forum.com/f4/bog-dow...solved-166431/

https://www.f150forum.com/f4/humming...cks-up-162141/

Lots of reading but it seems a common issue.

smithka

There seems to be more of a rattle than I originally thought. When I have the window down it almost sound like something spinning with friction. It also does not always get louder/worse with higher RPM. I would think if it was air box seals it would be relatively constant, right?

Thanks again...