Hello -
I have 2009 F-450 6.4L Diesel with 41K miles and just started to have a noise that can be heard up in the CAB of the truck while driving or idling. It sounds like a dry ball bearing that would go bad in home computer AC power supply or CPU cooling fan. The sound starts when the engine is at full operating temperature and most noticeable and the loudest if you are standing in front of the engine at idle outside. Checked all fluids and they are normal. Turning the steering wheel doesn't affect the sound either or turning off the AC. Check engine light has not come on. The only thing I have noticed is that clutch fan stays on a very long time after starting cold and takes about a mile or two before it disengages. The truck is only used to tow a 36' 5th wheel and sits the majority of the time. Has anyone had this problem?

 

Have you had a look at your micro-v-belt idlers/ tensioners? My 7.3 had that kind of a noise and I used a good graphite spray lube and it never came back. Now saying that there are 2 tensioners on the 6.4 and when the tensioner went bad it was flopping around and throwing the main belt off. The other kind of noise like that that I've is the electric vacuum pump wasn't tighte down but that shuts off after it pressures up the system or times out if there is a leak.

 

thank you for the reply. I did check the tensioners and they are good. The belts were replaced at 40K. I did go and out start it after you reply and check the vacuum pump doesn't appear to be it. The sound is coming from the very center of the front of the grill.