Whine from engine at idle..alternator?

Started the truck yesterday to go to somewhere about a 15-20 min drive. I noticed a whine noise from the bay first thought was PS but I hadn't moved yet. Then I noticed it changed with throttle and my interior battery gauge was at the hash mark above 9v. Had to go, away I went whining the whole drive. No driving issues other than the noise. After leaving 45 min later everything started up fine and still whining most of the way back home, then it went away and I noticed the gauge had went back to center and everything was back to normal.
Finished the evening with replacing the door regulator, having the door open and key on for testing window operation etc. I drained the battery enough that it just clicked when I went to start up (few hours later) so I wasn't surprised. threw it on a charger for 15 min or so and it started. Fast forward to today....just went out to get some readings.
Initially testing I was getting like 4.5 volts at the terminals but I'm chalking that up to my leads not getting a great connection or a cold battery in the meter? I went and started it and it fired right up. Brought the meter in and warmed it up. Still had to poke into the terminals a bit to get consistant readings:

12.3 volts off
13.2-3 running at idle
13.9 lights on blower on high with rear defrost on

No whine when starting today....slight whine when more load is placed on but not near as loud as yesterday. Am I looking at an alternator going out?
From the numerous posts and things I've read online there are various reasons that people had voltage fluctuations but most of the posts didn't seem to have a whining noise coupled with them. Going to run up to AZ and have it tested. I believe I have the larger alternator so they may not be able to test it..

One more note:
No battery light on on dash except like normal before starting

 

12.3 is a pretty dead battery if it was just running, I would start there.

 

Go on then, satisfy my curiosity, why is it that you believe that whoever is going to test your alternator might not be able to carry out said test if the larger alternator is fitted??? Does your mechanic use his tongue on the terminals to determine output?

Bear in mind that anything driven off the auxiliary drive belt increases with engine speed, so a whine could come from the alternator but don't rule out water pump, tensioners, power steering pump, a/c pump etc, etc.
I seem to recall, from the far distant days of my youth, that judicious use of a lubricant, applied (as best as one could access them) to the bearings of each item on the drive belt, NOT the drive belt, one at a time would highlight a failing bearing as it will temporarily quiet a failing bearing. BUT I can't remember what we used as a temporary lube, probably WD-40 and obviously you can only test one item between each stop. Google or someone else on here might well be familiar with whether this is an approved US shade tree mechanic's trick.

 

I'll be as kind as I'm going to be in the new year as a resolution. From the text, no tone or inflection obviously it sounds like you're being an jerk. That's all you get sorry.

Anyways, as I said this info is all from others experiences...maybe I shouldn't have thrown that in there but I read that some had that issue at AZ (Autozone).
I do appreciate the last part, I do understand that those may be culprits also. I suppose it's feasible that anyone of them could be intermittently whining? My thought was that being as the voltage gauge was acting strange that it was likely a failing alt over a battery. I don't see a bad battery causing this noise but then again I'm no mechanic, just here to learn and help when I can.
Will be replacing battery tomorrow, it's a NAPA Gold pos and about 3 years old with a slight bulge that I recently noticed while calling about warranty. So maybe I have 2 problems. Not quite there yet.

 

Definitely a battery to start. Especially if you have a bulge which means it either had a violent reaction inside and quelled itself before going into thermal runaway or the acid froze at one point (stupid winter temps). In any case, it will die at the most inopportune time. After you get the battery in, take it over to a place that will test the charging system. 13.9 out of the alternator isnt horrible, even with a dead/ half dead battery, but it should be above 14 at least. BUT, that may have been from your meter, so call it questionable but worth checking anyway.

 

Yeah, bulges in batteries are, in my experience, never a great sign.

I did wonder why you were going to Arizona to test your alternator, oh the joys of an abbreviated culture, I mean, that wouldn't be too bad if it's just a trip over the state line but...



I have never used an auto store to test my batteries, alternators, replace bulbs or wipers, mostly for the same reasons that I'd never ask the staff in my local Waffle House to do those things, although some of them are probably far more reliable for that kind of work than some of the staff I've met in some auto stores, just because the store says they can do these things doesn't mean that they should be. Obviously that doesn't apply to all auto store staff but I'm sure you get the idea.
Anyhow, I'm sure by now that it's apparent to you that for someone used to taking his questionable alternators to an alternator guy rather than Jody in the goodies store why I'd question their ability to test larger alternators.

Once upon a time I'd have recommended a drop test on your battery but modern batteries seem to be a lot more fussy than the stuff I was playing with last century and it usually turns out to be more hassle coaxing a few more trouble laden miles out of a questionable battery than just forking out for a replacement while the old thing still has some life. Once you have a reliable power supply you'll be able to focus on anything else that's driven off the aux belt.

 

I have a 2006 DC 4.7 and have been running an Ultraguage for 3-4 years. I don't think I have ever seen my voltage go above 13.9 on the Ultraguage. If it gets to 14 or higher is has been a rare occasion.

 

Indicated battery voltage is not a reflection on alternator output. My Haynes book of lies specifies an upper output of 14.8v for the alternator.

EDIT: That's the given specs for a 2nd gen, although I doubt if the 1st gen is much different, if any.

 

If Haynes and Chilton got into a fight... Who would win

You are correct though. 13-15 volts, but usually around 14.5 normally, is what normal run of the mill vehicle puts out. Obviously, this does not take into consideration corrosion on the terminals, line loss, low RPM and other stuff. Just normal typical operation....

 

2005-06 Toyota Factory Service Manual
Check the charging circuit as follows:
With the engine running from idling to 2,000 rpm, check
the reading on the ammeter and voltmeter.
Standard amperage: 10 A or less
Standard voltage: 13.2 − 14.8 V

 

Mine runs at 13.9-14.1

Battery reads 13.1 right after running, will fall to 12.6 overnight. Its a seven year old battery.

I should probably do something about that now that I think about it.

 

Sounds to me like a stint with the conditioning cycle on the battery charger/jump starter/conditioner machine might be in order? ...

 

This is where my new battery is at as of this evening. 14.1 is the highest, 13.9 no throttle. Dips down to about 11.xx when I start it. Haven't heard the whine since the first day I heard it. I'll check my overnight voltage in the am.

 

https://youtu.be/kmcU1v8B8Mc
Little video of today. No whine, haven't had the alt tested yet but it seemed to do the dropping while driving at stop signs. Video was taken sitting in driveway. Torque app didn't show anything under 12.9 -13.1 while all this was happening.

 

Look familiar?

If that video looks familiar, look at that thread, not just that one reply. I'm not the only one.

Mine stopped doing it when I went back to a 130A alternator. My truck originally came with the 130A because I have tow package. When I was in a pinch and my factory 130A caught fire, I was traveling and had to get it fixed, so I took it to the shop I use when I don't have time. They, I later found out, installed a Denso 100A, even though I told them to install a 130A. My fluctuations stopped being so severe when I went back to 130A. I only noticed it when at stop lights usually, with headlights on and my brake lights lit, and when I had other things on like the windshield wipers, radio, fogs. Lots of fluctuation. And that was with a new NAPA Gold battery.

 

PS - have you ever replaced your alternator? Do you know what size alternator you have currently?

 

Agree. Looks like a weak alternator. Time for a new one.

 

Yup, looks about the same. Mine dips quite a bit more at times. Gonna run it through my friends shop I don't have time to mess with it as soon as it needs done. It doesn't look that hard of a replacement but at least it'll have a labor/part warranty on it if it runs through the business.

Toyota login shows 130 Amp due to tow package also but I haven't changed it can't tell visually yet if it's the 130 or not. Just gonna get a denso remanufactured sounds like we can't get a brand new according to what he remembers. Will look it up today.

 

If you really want to know if it's your alternator that's whining, you could always try popping off the serpentine belt for a minute and run the truck. If the whine goes away, you know it's something with a pulley on the front of the engine. However, that could be any pulley, alternator, power steering pump...

Stress to your mechanic you need them to install Denso 130A. Depending how many miles you have, you could be overdue for a replacement. But seriously, I think when I swapped out the 100A my mechanic installed for the correct 130A, it took me all of 45 minutes, from start to finish. And I put in a new green Gates HD serp belt too.

The job is easier if you remove the passenger front splash guard. Gives you instant access to the wiring via wheel well. Hardest part is finagling the power steering pump out of the way. Other than that, it's just removing and reinstalling some bolts, and the serp belt. Serp belt comes off anyway, hence why I replaced.

 

Yeah it's for the 130a. Serpentine belt is like 3 years old. I wish I had time to do it. All signs really point to alternator. Just bad timing. I'll play the shop game this time to the tune of 750....the book of "it takes this long" makes that money. It all comes back around.
Now to find an older Lexus of accord etc. To save gas and have fall back car that allows truck to be down. Problem is everyone still wants close to MSRP still lol.
Will update.

 

This was my issue too, had to travel for work, and I defaulted to the same, using a trusted shop I know, but paid a couple hundo less for parts and labor. I get it. Definitely no judgment from me.

Unfortunately, as I found out far too late, other than installing the weaker 100A alternator, I'm pretty sure one of his guys lost or failed to install the bolt for my alternator harness bracket, so it was just dangling all over the place, and I'm pretty sure they also ripped out (literally, ripped) my front passenger splash guard. This specific shop has never screwed me like this before when I've dragged in my wife's SUV or previous pickups when I didn't want or have time to do the work.

I'll probably go back to this shop if I was in a pinch, but I'm still kinda pissed about it. I'm that guy, when I don't have time to do the work, and I'm kicking it to them, I always bring in a suitcase of cold beer at pickup. They know me well, so I'm a bit disappointed, and haven't been back since pre-pandemic when I took the truck in for the alternator. Their loss, I guess...

 

Sorry that happened. I totally see why you could be pissed. Hopefully this all goes smoothly and they treat things with care.
I'd say their loss. People not having time that normally do their own work that also take care of their vehicle pays their bills and makes their jobs easier most of the time.

 

Well I got the truck back from the shop. No weird whine but then again I haven't heard it but that one time. Voltage seems about the same as before according to veepeak app on phone. Battery gauge still drops some at a stop light here and there with everything I can turn on being on. Hopefully I didn't just throw money at it for nothing. Time will tell I guess

 

My steering pump whine sounds like a whale in heat and is always there except on warm days. Someday I’ll get around to replacing it. Hopefully not in the dead of winter.