Engine squeak/chirp from top rear of engine.

Hi all I have been chasing this noise for a couple of months now. Has any one else run into this and found a fix,(See below)

Issue:

"When the engine is cold, I hear a repeating metallic squeaking or chirping coming from the area of the rear of the engine. This is the 4.0L OHV V6.
After
about 5-10 min of driving, it goes away. Sometimes, it's gone even for

several days - even when cold.

The chirping goes about 400 - 450 times a minute as the engine is idling at about 800-900 RPM. That tells me the chirping is happening at half
crankshaft speed. The spark plugs, fuel injectors, and valves all do
their
thing at half the speed of crank rotation, so I suppose any are suspect.


Using a Mechanics stethoscope against-the-engine block head and intake, I hear nothing inside like a clattering valve or bearing, and no chirping.
But can still hear the chirp when just standing there listening.


I listen with the stethoscope to the injectors and you can clearly hear the rapid tic-tic-tic-tic-tic of the injectors (that's normal). But I don't hear the chirp, only from the back of the engine without the stethoscope, as
if it's external to the engine. The ticking of the injectors is in
sync to
the chirp repeating, so that verified for me that it's at half crank speed.
Seems to regular to be a rubbing part on the outside of the engine.


It's not the serpentine belt - we even pulled it off and started the engine for a couple second without the belt - and we still hear the chirping.
So
that rules out any of the belt-driven accessories and the idler pulley and tensioner, as well ruling out the water pump.


Question is, can a fuel injector squeak? I can't imagine it's the cam
or
the lifters or the valve guides, as they are all bathed well in oil.
Plenty
of oil per the dipstick, and plenty of oil pressure per the OP gauge. "


Thanks for any clues...


Myk

This will get you down the right path

http://www.explorerforum.com/forums/showthread.php?t=161590&highlight=bird+chirp

4xmadness, I had gone through this on our 96X with the 4.0 OHV. I had purchased the complete cam synchroizer from RockAuto but could not get it to work. I had taken the original one apart and clean it but this only last 1 day of no noise. Please see this thread. This may help even though this was originally for the 5.0L.

Thanks to all who replied, I did order the DORMAN OEM REPLACEMENT CAMSHAFT SYNCHRONIZER from Auto value, it was $90.00 Canadian, it came with a complete syncro assembly, camshaft position sensor and alignment tool. I opted to replace the upper and lower intake gaskets at this time as it made for much easier access and there was a slight leak at the front of the intake, worked great, you could feel the bearing was shot in the old Syncro

4xmadness said:

Thanks to all who replied, I did order the DORMAN OEM REPLACEMENT CAMSHAFT SYNCHRONIZER from Auto value, it was $90.00 Canadian, it came with a complete syncro assembly, camshaft position sensor and alignment tool. I opted to replace the upper and lower intake gaskets at this time as it made for much easier access and there was a slight leak at the front of the intake, worked great, you could feel the bearing was shot in the old Syncro

Click to expand...

How long ago did you do this repair? I'm in Calgary as well and may require some advice on the repair.