Engine has 113,000+ miles on it.

The front crankshaft oil seal needs to be replaced - there is obvious evidence of it losing oil from that area.

The crankshaft pulley seems fine - it's not wobbling nor is it making the other weird noises people have reported.

The noise I'm hearing is metallic - sounds like a bearing going bad on a pulley or idler wheel - which is what I thought it was until I looked at it closer...

It's in the vicinity of the crankshaft pulley - judging from the pictures I'm looking at, it sounds like it's coming from where the timing chains wrap around the crank.

Doesn't seem to be affecting the way the truck runs - it runs great. Just makes that annoying noise.

I've given it an oil change - it was very badly needed.

Anybody have any ideas? Is it something to worry about?

 

Metallic screech is not a good noise to hear. I would borrow a listening microphone with ear muffs and listen closely around where the noise seems to be strongest. A long screwdriver held to the ear might work as well but is not my favorite method. After determining where it's strongest think about what is moving in the area and plan accordingly.

My 4.0L only has 90,000 on it and some from before 2001 have problem with chain noise that generated alot of complaints.

 

i have no real knowledge of that particular engine but it might possibly be from your water pump.I have heard bearing noises from water pumps before....they werent terribly loud though but without a doubt thats what it was.----you might take the belt off and stat spinning things with your hand checking for rough spinning/noise etc--good luck

 

Remove the belt, and start it up. If the noise is no longer present, spin the components to check for bad or dry bearings. If the noise is still coming on strong, the problem may be behind the timing cover.
I think you may also want to pull the crankshaft pulley and see if the keyway in the nose of the crankshaft has been damaged, or the keyway in the pulley worn. At least you have eliminated many things by these minimal tests.
tom

 

Seeing as how this is the ohc 4.0L, I wonder if it's a chain tensioner problem, which the early 4.0L were noted for, so maybe add it to your suspect list????

On the crankshaft seal leak, if it's not too bad, maybe consider trying a "high mileage" recipe crank case lube, that has seal softening/swell additives, if it's not too bad maybe they could slow, or stop it for a while.

 

I'm leaning heavily in this direction. I can put my ear right next to where the noise is coming from and it seems to be where the chains wrap around the crank - like maybe there's a bit of "slop".

Didn't think about pulling the belt, but I'm pretty sure I've found where it's coming from - I can put my ear right next to it...

I have a stethoscope I could use. It's not a screech - more of a irregular metallic bearing-like or chain-like "clicking" - not sure if "clicking" is correct either, but it's not a screech - nothing that would seem to indicate immediate catastrophic failure...

For some reason, I didn't come up with any chain noise issues when I did a search on the forums - I guess I didn't use the right buzzwords...

The more I think about it, the more I'm leaning toward chain noise...

Time to do some more research...

Thanks all

 

Read through these threads for a wide range of possibilities on your "marble noise" sound. Ford Truck Enthusiasts Forums - Search Results

 

Did a search for "marble noise" and read up on it. Interesting reading...

Engine purrs like a kitten - noise is not a knock. I don't suspect wrist pins or carbon. Noise is not coming from the valve train. Oil is 5W-30.

I broke out the stethoscope and did some digging around...

The noise is definitely timing chain rattle. Ford says this is normal? Well, if it doesn't cause any major issues down the road, I don't see much use in worrying about it that much...

Thanks for the help guys.

 

Maybe check with your Dealer to see if you qualify for a no cost tensioner replacement, Ford reworked a lot of engines for this problem. It too sorta had the "marble noise" sound.

 

From what I've been reading, the problem was mostly with the '01 and '02 models - supposedly, it was fixed by '03 (redesigned tensioner with more springs.)

There was a TSB out for the tensioners but I think the vehicles mileage had to be under 100k miles. I don't think this TSB covered '03 or later engines.

The '04 models had a TSB out for re-programming the computer to correct a knock condition that simulated the chain noise but I'm pretty sure that's not the problem here. Wouldn't hurt to check anyway...

I'm also reading that the "fix" didn't really fix the condition - It seems a lot of folks had a problem with the noise returning...

 

Yes on Rangers it was mostly on 01 & 02 models, because 01 was the first year the Ranger got the OHC 4.0L, but the same engine in the Explorer had problems way before that, so there is a long history of tensioner casset problems on the early 4.0L OHC engines!!!!

Yup we too heard that the problem was supposed to have been fixed by 03/04 & the complaints about the noise on the fourm did drop after the "fix", so maybe consider doing, or having it done for your own piece of mind, as that engine has lots of life remaining in it!!!!