Weird Engine Sound I could use a hand in identifying

[Explorer0204]

Hello everyone,

So here's what I got.
2004 Explorer 4.0L Flex Fuel model (I believe)
66300 miles.

I have a weird marblish kinda rattle engine sound that has developed. It sounds like someone is taking a steel ball bearing and swoosh in it around in a steel cup kinda. Check out the YouTube video you can hear it.
Engine is all stock.. As far as I know anyway (no reason to think otherwise)

When it makes the noise:
I think it makes the noise all the time. You definitely hear it most AFTER the engine has dropped from high idle. You can somewhat hear it on startup but I think the fan is too loud for you to hear much.
This noise can be heard anywhere outside the vehicle and at intersections with the windows down at intersections, but it is not loud enough to be heard in the cabin at speed.
It speeds up with engine rpm a little possibly, but doesn't seem to be too dependent on engine rpm.
It sounds like it is coming from the bottom of the engine or the middle.. But lying underneath the sound reverberates on the ground so I can't really be sure if that is where it is coming from.

What I have done so far:
Took the serpentine belt off to eliminate any pulleys from making noise. After doing that the truck still makes the noise.
Inspected the harmonic balancer per the threads on here and it looks perfectly fine, plus that is more of a squealing sound when they go bad not a metallic sound from what the threads say.

Notes:
What Baffles me is that the truck runs Perfect. No noises good power transmission shifts good...
I'm baffled as to what it could be.

I wish I had more I could add but this is all I really can figure out. Thanks for any help.

Engine sound: http://youtu.be/xbRqTjEVjEE

 

[FordFool2]

I suspect a bad bearing in either one of your idler pulleys or the belt tensioner. Both are easy to replace and do not cost very much.

Take the belt off check each pulley by spinning and feeling for excess play.


OOOPs....I should have read the entire post. Belt already taken off.

 

[broncojunkie]

He said it makes the noise with the belt off, so doesn't seem like it could be a pulley. Get yourself a stethoscope ($4 at harbor freight) and start poking around. You can probably pinpoint it that way.

 

[Explorer0204]

He said it makes the noise with the belt off, so doesn't seem like it could be a pulley. Get yourself a stethoscope ($4 at harbor freight) and start poking around. You can probably pinpoint it that way.

I tried but can't really seem to find the noise. If it is the tensioners I don't know what I'm gonna do...

 

[Grea]

Depending on the the engine you should check the timing chain tensioners...I've had a couple v6 exploders and the last one i had made that sound.. I couldn't figure it out for the life of me until finally my brother and I ripped the motor apart and found that there are theese timing belt tensioners in the front of the motor that are made of plastic and over time break and crumble.... Leaving the chain loose and running over a sharp edge making that clacking ball bearing sound.. Also the loose pieces of plastic were bouncing around as well.... The parts were cheap from the dealer but it was a pain figuring that out and tearing everything up.but it was fine after that..... Also i believe some engines have a hydraulic chain tensioners. That need fluid and rpms to apply pressure to the timing chain and over time those go as well leaving slack in the chain causing it to bounce around... But i don't know much about those...best of luck man.. Tell us what you find so we can learn and spread the knowledge to others.

 

[Explorer0204]

Depending on the the engine you should check the timing chain tensioners...I've had a couple v6 exploders and the last one i had made that sound.. I couldn't figure it out for the life of me until finally my brother and I ripped the motor apart and found that there are theese timing belt tensioners in the front of the motor that are made of plastic and over time break and crumble.... Leaving the chain loose and running over a sharp edge making that clacking ball bearing sound.. Also the loose pieces of plastic were bouncing around as well.... The parts were cheap from the dealer but it was a pain figuring that out and tearing everything up.but it was fine after that..... Also i believe some engines have a hydraulic chain tensioners. That need fluid and rpms to apply pressure to the timing chain and over time those go as well leaving slack in the chain causing it to bounce around... But i don't know much about those...best of luck man.. Tell us what you find so we can learn and spread the knowledge to others.

I'm real afraid it is the tensioners

What sucks though is I have zero time to try to research/diagnose/fix this stuff thanks to being an engineering major and having two tests on Friday. I commute 40 miles a day too and I hate to drive it, luckily I do have access to some other vehicles and I have a motorcycle but still.

I friggin love this explorer and all I ask of it is to get me out of college trouble free then whatever wants to break can break.. Guess we will find out eventually if that will happen.

Anyone know good ways to forge money? Heheh.

Thanks for the input guys I think I am going to have a friend who is a mechanic have a listen and maybe fix it if I decide I just can't fit it in time wise.

Pulling an engine to replace the timing chain tensioners isn't exactly a weekend job for me..

 

[Explorer0204]

I forgot to mention one of the most important things! It idles rough from time to time...

Somehow I didn't relate that to the tensiners but I think it is very possible the two could be related

 

[Explorer0204]

Good news everyone!

I took Dora over to my buddy's house and he was checkin' er out and he stuck his finger in the harmonic balancer and sure enough, something is broke and rattling around in there. You can duplicate the sound with the engine off using your finger. Looks like I just need to replace the balancer and I should be good to go. I'm elated right now as I love my little 6 cylinder and can't afford a big repair!

Thank you all for the help and I will make sure to tune in after the install verifying if the noise is gone.