This is driving me crazy. After about 1 minute after starting the truck it sounds like the fan belt is squealing..(below 30 deg outside) Only its not the fan belt as I replaced it. Does not do it when it is engine is operating temperature. Have checked all of the Pulleys which seem to be all right. The frequency of the squealing sound is about 1/3 the engine RPM and will go away above 2k when it does do it. Stopping at a stop light after about 45 seconds it really starts to get loud.
Has anyone ever heard of a Fan Clutch do this.. I beleive that this engine has a timing chain right? Any suggestions are welcome.

 

Welcome to FTE!!!

I would suggest cleaning the pulleys with a small wire brush and some brake cleaner. Dirt can accumulate in the grooves and cause belt squeal. Do this, of course, with the engine off.

 

Just before I bought my '00Ranger 4x4 3.0 in November, I drove it, and it too, made the same noise.
I pulled it into my garage to have a listen, but couldn't find it.

I took the truck back to the dealer and told him about the noise.
He gave me some 'mumbo-jumbo' about an I-O-U to get it fixed when I buy the truck.
NOT! I told him when the truck is fixed, I would drive it again, then decide.

Turns out to be the bearing on the alternator!!!
They replaced the serpentine belt. . . didn't do it.
They replaced the belt tensioner. . . not.
They replaced the alternator. . . . it's as quiet as a little ole' lady in the back of the church!!! (My Mom!)

Worth a 'look-see'.

Good luck!!

 

Both of these suggestions are good ones.. Every time I go to isolate it stops..
But I will be ready.. Will post what it is when I finally nail it down.

Thanks again

 

If you do a search on this, you'll get lots of hits...

Mine squeaked, especially when it was moist or humid out. And it actually sounded like the belt cause it had a pattern that sped up when reving the engine. I replaced both the tensioner and the idler pully (Which was crooked to the naked eye) and it's ALMOST gone. I can hear it slightly when it's wet out...

 

With some personal experience with my...'99 3.L ..
I've noticed a more and more of a "squeal-less" truck with the replacement of these items:
*Water Pump (Bearing related)
*Thermal fan-clutch (a whining noise was eliminated)
*Idler pulley (a lite squeal was eliminated early on @92K)
*Alternator replacement yielded a minor loss in "avg-engine noise/squeal"

Stats:
'99 Ranger (in process of head removal due to possible crack #5cyl )
3.0L
163K
SC - Amazon Grn

 

.....On a further note...
I noticed at avg. belt changing time...the engine did not take too well to the OEM belt, but instead ran quieter and tighter with a belt that cost a qtr of the price from an Autozone part store here (Kelly Springfield Belt) $16.
Ive tried belts from:
Napa $32
Pepboys $20
Advance Auto $18
OEM belt $51
(all in 2mos.time) with the Autozone belt being the quieter and tighter belt.

 

Turned out to be cam synchronizer on my 02 Ranger

 

Finally, an answer, whew, I've been waiting.

No, but seriously, it's a good thing to have that squeal diagnosed quickly due to the cam sychro being a prime component of the oil system of the 3.0L

 

so you mean the belt squeaked over the alternator? or a bearing in the alternator was bad? i seem to have the same thing, replaced betlt and tentioner and it went away, now with 15,000 miles its coming back when i start it up????

 

I would suggest first, to use a rag/soft bristle brush and brake cleaner on cleaning pulleys. Dont want to scratch the surfaces. Second, use a piece of heater hose to search the engine for the noise. One end to your ear another going over the engine until the sound gets louder. Ive had idler pulleys, tension pulleys, belts, alternator bearings, ac bearings all make noises like what you describe. Good to rule them all out first. If the bearing starts to go it can cause the pulley to become slightly misaligned and get noisy or the bearings themselves can do the same. Some very minimally applied wd 40 to the pulleys at the belt contact can also give you some info (spray it on the belt drive surface and see if it changes).


As pawpaw says, "more thoughts for consideration"

 

Try posting a walk around audio / video of the engine bay, more attention to the area, or item where & when the noise seems loudest, so we can all hear & see what you are.

 

on my 2000 3.0 it is the back side of the belt that squeals during certain temperature & humidity conditions.
specifically, it's the part of the belt where the info is embossed, it has a different friction surface that squeals when it goes over the smooth pullies.
cleaning or buffing the printed sections on the belt didn't do much, lessening the tensioner made the noise go away but I couldn't
drive it while very carefully holding a wrench on the tensioner.
to test apply light touch of a wet something to the belt.
I used a piece of paper towel that would tear away easily if the belt grabbed it.

 

I have a bad squeal coming from my pulleys I have put new belt and tensioner replaced and it still squeals but it I take bar soap and run under the fan belt while the truck is running it will stop squealing anyone one have any idea what it is?

 

Get a ContinentalElite=GoodYearGatorback SerpBelt.
Quality+Grippy+Quiet.
Spec a belt length maybe 1or2cm shorter than what you have now.