Ok so....
Last week, on the way home from Redmond I noticed this increased sound from the engine area. Sounds like a bearing Bzzzzz sound.
Has been averaging 95*f for the last few weeks.

Then I notice that the battery is slowly loosing voltage as I drive.(scangauge2) Thinking the alternator went out. Front driver side engine bay area for the Bzzzzz sound.

Replaced the alternator with a Rockauto Denso reman. Looks identical.
Seems like its is charging now but it still has the Bzzzzz sound...like a bad bearing or something...That I thought was the alternator...wth?

Went through all the fuses and they look good.
Wire to engine bay fuse box looks good.
Pulled the fan belt and spun all the idlers and any spinny parts I could and it all sounded fine...no grit/resistance in any of the bearings.

I am at a loss...going to fix the grounds and see, some corrosion and separated strands...why the noise though?

So thinking I would just upgrade the wires like I have seen a few other T4R members do..."the big 3".
Went to the local stereo place that had $8 a foot for 0g...I decided I didn't need to do that.

I am going to just do the Negative side ground now to see if that helps any.
It has a bit of battery acid in it after the Optima fail I had.

Any ideas would be great!

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Or try the idler pulley, The bearings go bad on those

water pump?
hope you had the battery fully charged by an actual charger and not the alternator. you can kill new alternator with a dead battery.

That's what the guy at the stereo shop suggested too.
I guess that's the next step...it is right next to the alternator.

I did the water pump a few years back. Was dripping.
Battery was charged prior to new alt install.

The fixed ground did nothing. I think I was trying to convince myself this was some sort of resistance issue.

My stereo has been tuning on by itself, never off.
Some times at car start up sometimes just driving down the road.
My T4R dash computer was reading a nice 77*f outside the other day and it was actually 96*f.
The Scangauge2 was reading 132*f ,parked and idling at the intake.

I have been wanting to do the pulleys and idler just due to age (sept 2003 built) guess I will now.

I’d start with the pulleys too!

My pulleys made the same sound! Replaced the bottom one since the dealership had recommended it when I had them replace the serpentine belt. Truck still had a squeal after I put the new pulley on, took the belt back off and noticed top one was going out too. Called around and no one had one in stock oddly enough, so I just popped the seal off and greased it up. It makes a slight whirring sound still sometimes but it’s tons better.


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We have a winner!
Hope I am not jinxing myself...not done yet.
Just got all excited and had to dump some pics.

Bad Pulley bearings you say?
I think the leaking water pump introduced antifreeze into the bearing at some point. Can see wet/rust marks. Blue arrows in pics. Also a white powder...dried antifreeze.
I just pulled the bottom pulley and found this mess.
Cleaned it up and stuffed in my favorite Purple grease.
Will order up new bearings after I go back and read a few threads...seems like there was a bushing sleeve issue...

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That is exactly what mine looked like when I opened it up.

I think you found the culprit!

Still have a tiny, grrrrrr sound but I may just be hypersensitive now.

I think its fixed.
Cleaned the #2 and #3 idlers and the tensioner bearings.
The seals on the tensioner bearing was not friendly, bent and tore it a little...whoops.
The others were easy.

On mine OEM bearing are...
Tensioner= Koyo BD17-31DUM8
Idlers= Koyo 6302RMX
No.1 idler has 2 bearings stacked (pics above)
No.2 & 3 have 1 bearing (each)

Also wanted to say that the worst part of this was just getting the fan belt back on...pita.

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Following up on this.

I was thinking I would get the OEM alt rebuilt or get a rebuild kit and do it myself.

Took my OEM alternator to a local, long time in business, auto electric shop.
They said..."we don't even touch alternators any more, try this other place..."

Went to the other place, complete other side of town, he said... "we don't rebuild or repair these any more."
Tested the alt and it tested 'good'...bah. Said the belt kept slipping, smelled like burnt rubber when he handed it back to me.
It did not spin half as freely as the new reman unit.

Then looking for bearings and reading about the sleeve issue some have had.
I found the exact same bearings, Koyo 6302RMX, as was in the idlers and the tensioner/BD17-31DUM8, so I ordered up a set (eBay) and will just replace the bearings.
No sleeves needed.
$18each for the 6302RMX and...wait for it... $45/ouch, for the BD17-31DUM8.
My thinking is ease of installation and original parts/pulleys.

Guess I am a glutton for punishment.

In case anyone wondered the difference between the black and red seal Koyo 6302RMX bearings.

The ball race is metal instead of plastic and there was not much of some type of clear grease.
Cleaned it out and did the UPG Royal Purple.

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Went to install the new black seal bearings...not only do they not work I found out to much lube is a bad thing.
Grease is starting to get all over the engine front, from my re-grease, guess I will try 'less is more'.

The inner race is to large on the black seal bearings and comes into contact with the pulley.

Wishing I would have just gone that Gates pulley kit route now.

Pulley= 23.5mm
OEM koyo 6302RMX (red seal)= 22mm
New koyo 6302RMX (black seal)= 25mm

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Have you touched the fan clutch? You seem like you have too much time on your hands so why not go all in with the bearings/pulleys?

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Fan clutch will be next on the list no doubt.

Originally I was thinking I could just get the bearings, swap them out...I have a press, save a buck and have less issue with any kind of fan-belt alignment problems.

A quick search online and I find the bearings on eBay...so as per my normal routine I went with the cheapest ones I found, black seal for $18...WHOOPS!

In case anyone wants an actual same as OEM Koyo bearing, this guy has a couple...
https://www.ebay.com/itm/NEW-Koyo-Re...8AAOSwZlZaH1yN

BTW
Not all red seal 6302rmx are the same, one was the same dimensions as the black seal...the reds seem to be a plastic bearing race with a bearing shield on one side ...the black seal are a symmetric steal bearing race...at least the ones I bought that is.

Also I will note that the tensioner bearing I bought looked good however it did not have 'JAPAN' on the seal...

What if the sound is your timing belt/chain?

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