My 300 I6 ('84 Bronco) is making a chirping noise that follows the engine speed and appears when the engine is warmed up. The chirping happens w/o any belts attached, so I'm kind of lost as to the source. I saw mention of rockers, but I can't detect any of chirping noise coming from the oil file hole either. The chirping is much louder than in the video after its been driven for a while

Any ideas of what else to check?

 

Check the fuel pump arm and excentric.

If nothing pull the valve cover and look for obvious signs.

 

Thank you. Since posting that, I've narrowed it down to the balancer/front main area. The crank timing cover seal appears to be leaking a little bit of oil too. I'm working up to replacing the balancer and timing cover seal.

 

Be sure to get the timing cover seal gasket with the crankshaft repair sleeve.

 

For posterity's sake:

I'm 99% certain the timing cover crank seal was the problem. I've put about 50 miles on it, and the chirping noise is gone.

I replaced the timing cover seals and harmonic balancer. The previous harmonic balancer looked fine. The rubber was still pliable, and there was no obvious reason for it to be causing the chirping.

Thanks everyone for the help. I appreciate it!

 

Thanks for the update.

 

I wonder if the timing cover wasn't 100% centered. It wasn't offset enough to chew through the seal, but was enough to cause a rubbing (chirp).

Either way, glad to hear that seemed to take care of it, and thanks for updating us on your success!